Watering Street Trees in Santa Monica

Watering trees is extremely important to their growth, health and ability to produce the important environmental benefits that we as a community rely on. However, like anything else, too much of a good thing can be detrimental. By following some basic guidelines you can have healthy street trees and conserve water at the same time.

FUNDAMENTALS OF WATERING STREET TREES  The species, age of tree and type of soil have a bearing on how much to water. o Some types of soil hold water longer than other types. o Some types of soil dry out quicker than other types. o Watering young trees is different from watering mature trees. o Some species do not require as much water as others might regardless of age.  See Attachment 1 for a list of watering needs of individual species.  To find out what species your street tree is contact the Community Forester at [email protected].

o The seasons and weather conditions influence when to water.  Checking soil moisture content throughout the year will tell when a tree needs water.

o Surface grade dictates how fast the soil can take the water.  Apply too much at once or too often and you get surface runoff or puddles.

KNOW THE TYPE OF SOIL It is important that sprinkler systems are properly designed and maintained so they apply water at a rate low enough to allow all it to infiltrate into the soil without running off or creating puddles somewhere it’s not supposed to.

The rate at which soil can absorb or take in water is the infiltration rate. The rate at which a sprinkler system applies water is called the application rate. If the application rate is higher than the soil's infiltration rate surface runoff is achieved, resulting in water collecting on the surface and/or flowing away from where it was supposed to go. This wastes water as it doesn’t provide the tree with the water it needs. This condition can be offset by applying repeating shorter water cycles that gives to sol time to absorb the moisture in between cycles.

The irrigation system shown in the photo at left shows a front yard landscape with a steep grade down to the sidewalk. The system has been running long enough to pass the point of runoff and the water applied from this point forward is wasted.

To avoid this problem the system should be set with short cycles and long intervals in between each cycle. This allows the soil to absorb the water as it is applied.

In order to have an idea of the infiltration rate it helps to know the type of soil. A general rule to follow when applying irrigation is: sandy soil requires water on a more frequent basis and clay soils require less water on an infrequent basis.

An easy way to determine the type of soil:  Dig down about four inches and take a sample of moist soil about the size of a marble.

o If it can be rolled up into a tube thinner than a pencil and hold its shape, then its clay soil.

o If the soil breaks apart easily and has a consistent, gritty texture, it is sandy soil. o If the soil contains a lot of organic matter of varying size and consistency, it is loam. Loamy soil can also vary from clay loam or sandy loam.  Loamy soil that is easy to break apart into small particles is sandy loam.  Loamy soil that breaks apart into large chunky particles is clay loam.

Soil with the right amount of water should be moist but not saturated. A simple test to check moisture content is to take a handful of soil and squeeze it tightly then release the pressure. If the soil retains its shape and is not sticky or oozing water, the moisture content is favorable.

Another consideration is the seasonal changes in weather. During spring and fall, the days are shorter and cooler and the soil temperature drops, and trees need less water. As the days get longer and warmer, trees need more water. As the seasons change, the frequency of watering needs to be adjusted accordingly. This is usually done by reducing the number of days between each time you need to water and reducing the amount that is actually applied to the soil. If no adjustments are made throughout the seasons, over- watering or under-watering occurs, which in turns leads to poor tree health.

GUIDELINES FOR WATERING STREET TREES  Check the Community Forester’s list of water requirements for street trees to get an idea of how much water your street tree needs. (Attachment 1)

 Key factors to remember when watering street trees: o Species There are over 225 different species of trees in Santa Monica and many of them require different amounts of water at different times of the year. Santa Monica’s forest is primarily made up of trees that flourish in a moderate climate with naturally dry conditions. Many species found in Santa Monica do not require regular water and actually thrive when they receive minimal amounts. Other species require no irrigation during the summer months as it is detrimental to their health. Mature or established trees usually can get by with infrequent watering depending on the species of tree.  Most of Santa Monica’s street trees require a climate with long, hot summers and mild winters with a moderate amount of rainfall. They do best in sandy loam soil but can tolerate other types of soils.  The most important area to water for deciduous trees is within the dripline (from the trunk to the outer edges of the trees branches).  For evergreens, water 3-5 feet beyond the dripline on all sides of the tree.

o Current age and size Older trees are sensitive to increased amounts of water. Trees that have been thriving on a certain level of soil moisture and then subjected to increased amounts can respond in different ways.  Increased shoot growth adds new foliage and weight to the limbs in the canopy and increases pruning requirements. In order to reduce the potential for limb failures pruning cycles need to be increased.

 Too much water can also kill roots from lack of oxygen in the soil. Mature trees that suffer from too much water in the soil will respond with dead tips, dieback throughout the canopy and excessive leaf drop. In extreme cases, trees with dead roots can fall over.

The tree in the photo at right is a mature drought tolerant tree that has a sparse canopy and chlorotic foliage because of regular watering. This is evident by the dieback in the tips of the tree seen in the photo at left.

 The photo at right shows the trunk base clear of turf. This helps prevent damage to the trunk from water, lawn mowers or line trimmers and maintains a strong healthy trunk base.

 Water on the trunk can lead to decay if there are wounds at the base of the tree. This eventually weakens the trunk and creates a potential for total tree failure.

Water on the trunk creates conditions for decay to progress when there are wounds at the base of

the tree.  There are several fungal diseases known to afflict trees that thrive in of southern California’s climate. The diseases that infect these trees can cause considerable damage and even the demise of a street tree. These problems mainly arise due to conditions that are different from their native habitat. Conditions such as summer watering or excessive watering in the winter result in fungi, bacteria and viruses in the soil that trees cannot withstand or compete with. This condition can ultimately lead to the failure of a mature tree in spite of a healthy appearing canopy.

 The photo at right and below show the fruiting bodies of two fungi that are commonly associated with trees that have been wounded and suffer from internal decay. Improper or excessive watering at the base of a tree creates conditions for these fungi to grow and accelerate the decay process. When trees display these fruiting bodies it is an indication of extensive internal decay.

Report a tree with fruiting bodies of fungi. [email protected]

 The main thing that new trees need to become established is a source of moisture. Regular moisture allows a new tree to grow quickly by developing a consistent amount of foliage and shoot growth, while irregular watering forces the tree to only produce the foliage that it can sustain on minimal or infrequent amounts of moisture.

o Young trees that have been recently planted in the ground need approximately 10 gallons of water every two weeks.

o A simple method to follow is to fill up the swale (shown in the photo below left) around the trunk base with water and let it percolate down into the root ball. After it has all drained into the soil, fill the swale up once more and allow it to drain.

Follow this method twice a week during warm months of May through October and once a week during the cool months of November through April.

 When watering trees it helps to understand the following facts about roots.

o A tree’s root mass is its foundation and provides the structural support it needs to remain standing upright. Over watering leads to damage to that foundation and can affect the stability of a street tree.

o Most if not all of a street tree’s roots are found in the upper 2 feet of soil.

o Most, if not all roots are found where water, nutrients and oxygen are readily absorbed.

o The distances that roots can spread horizontally, and the spot where most of the moisture is absorbed, are directly related.

o Trees need oxygen for their roots. Too much water in the soil interferes with the roots ability to exchange oxygen, leads to root rot and the eventual decline or failure of a tree.

o The roots of a street tree can extend up to four times the diameter of its canopy which places much of the root mass in a front yard landscape. Watering a front yard landscape forces the tree to develop its network of roots under the sidewalk and in a front yard.

o Deep and/or infrequent watering forces a tree to develop a root system that is far reaching and/or deep.

o Regular water for a front yard landscape allows street trees to develop a shallow root system that does not extend any farther than it has to in order to reach a source of moisture. LEVELS OF WATERING  None o Exactly what is says. Trees that do not need water will thrive in dry soil are healthier and have a stronger root base. The tree in the photo at right doesn’t need watering as it gets all of its moisture from the adjacent landscape on the opposite side of the sidewalk.

 Minimal o Water applied by drip either through a designed drip system or a temporary watering bag in order to establish young trees.

o The amount of water a tree needs also depends on the season as well:  During the months of April - October: A short water cycle in the morning once or twice a week is the best.  During the months of November - March: No need for supplemental water during the winter season

 Occasional Flooding o Trees that need moderate amounts of moisture but are growing in poor draining soils perform better when the soil is flooded periodically, allowing a long period in between each water cycle to allow the moisture to drain through the soil. The tree in the photo at right requires occasional flooding in order to maintain moisture in the soil. However, it would not grow well if its trunk base was watered every day.

 Regular o Street trees that need regular water such as the tree in the photo at right, can thrive on what is usually applied to the average landscape. This develops shallow roots that have the potential to disrupt surrounding hardscapes that are within a trees normal growth zone.

o Regular water can also be applied through a drip system, or manually.

o To learn best management practices for landscaping and irrigating parkways read the City’s Parkway Policy (Attachment 2).

 Moderate o Street trees that need a moderate amount of water need regular water in larger quantities. Trees that need this much moisture are faster growing or develop large canopies.

 Ample o Exactly what is says, ample amounts of water. Street trees that need ample amounts of water will show signs of stress if they do not get the water they need. Trees that need ample amounts of water can have large canopies or come from a riparian habitat, the tropics or the northern part of California.

Supplemental Summer Irrigation Winter Irrigation Irrigation Botanical Name Common Name recommendation recommendation Requirements Acacia baileyana BAILEY ACACIA None Young trees only None

Acacia decurrens GREEN WATTLE None Young trees only None

Acacia melanoxylon BLACK ACACIA None Young trees only None

Acacia spp. ACACIA None Young trees only None

Acer palmatum JAPANESE MAPLE Occasional flooding Moderate None

Acer saccharinum SILVER MAPLE Moderate Minimal Moderate – Low

Agonis flexuosa PEPPERMINT TREE Minimal Minimal Minimal

Albizia distachya PLUME ALBIZIA Minimal - None Minimal None

Albizia julibrissin SILK TREE Moderate – Minimal None Minimal

Alnus cordata ITALIAN ALDER Regular Regular Regular

Alnus rhombifolia WHITE ALDER Regular Regular Regular

Araucaria bidwillii BUNYA-BUNYA Regular Regular Regular

Araucaria columnaris STAR PINE Regular Regular Regular

Araucaria heterophylla NORFOLK ISLAND PINE Regular Regular Regular

Arbutus unedo STRAWBERRY TREE Moderate – Minimal Moderate – Minimal Minimal

Archontophoenix alexandrae ALEXANDRA PALM Moderate – Minimal Moderate – Minimal Minimal Archontophoenix KING PALM Moderate – Minimal Moderate – Minimal Minimal cunninghamiana Bauhinia blakeana HONG KONG ORCHID TREE Moderate – Minimal Moderate – Minimal Minimal

Bauhinia variegata PURPLE ORCHID TREE Moderate – Minimal Moderate – Minimal Minimal

Betula pendula EUROPEAN WHITE BIRCH Regular Regular Regular

Betula spp. BIRCH Regular Regular Regular

Brachychiton populneus BOTTLE TREE Moderate – Minimal Minimal Minimal

Brahea armata MEXICAN BLUE PALM Minimal Minimal Minimal

Brahea edulis GUADALUPE PALM Minimal Minimal Minimal

Broussonetia papyrifera PAPER MULBERRY Moderate – Minimal Moderate – Minimal None

Butia capitata PINDO PALM Regular Regular Regular

Calliandra tweedii TRINIDAD FLAME BUSH Minimal - None Minimal None

Callistemon citrinus LEMON BOTTLEBRUSH Minimal None None

Callistemon citrinus 'Violaceus' PINK BOTTLEBRUSH Moderate Moderate Moderate

Callistemon viminalis WEEPING BOTTLEBRUSH Moderate Moderate Moderate

Calocedrus decurrens INCENSE CEDAR Minimal - None Minimal None

Calodendrum capense CAPE CHESTNUT Regular Regular Regular

Casimiroa edulis WHITE SAPOTE Regular Regular Regular

Cassia excelsa CROWN OF GOLD TREE Moderate – Minimal Moderate – Minimal None

Cassia leptophylla GOLD MEDALLION TREE Moderate – Minimal Moderate – Minimal None Castanea spp. CHESTNUT Moderate – Minimal Moderate – Minimal Moderate – Low

Casuarina cunninghamiana RIVER SHE-OAK Minimal Young trees only None

Casuarina stricta DROOPING SHE-OAK Minimal Young trees only None

Cedrus atlantica ATLAS CEDAR Minimal None None

Cedrus atlantica 'Pendula' CEDAR WEEPING Minimal Young trees only None

Cedrus deodara DEODAR CEDAR Minimal Young trees only None

Cedrus spp. CEDAR Minimal Young trees only None

Celtis spp. HACKBERRY Moderate – Minimal Moderate – Minimal None

Ceratonia siliqua CAROB Minimal None None

Cercis canadensis EASTERN REDBUD Minimal None None

Cercis occidentalis WESTERN REDBUD Minimal None None

Chamaerops humilis MEDITERRANEAN FAN PALM Moderate Moderate None

Chionanthus retusus CHINESE FRINGE TREE Regular Regular Regular

Chorisia speciosa SILK-FLOSS TREE Moderate – Minimal Moderate – Minimal Minimal

Cinnamomum camphora CAMPHOR TREE Moderate – Minimal Young trees only None

Citrus limon LEMON Regular Regular Regular

Citrus sinensis ORANGE Regular Regular Regular

Cordyline australis DRACAENA Regular Regular Regular

Cotoneaster lacteus RED CLUSTERBERRY Moderate – Minimal Moderate – Minimal Minimal

Cryptomeria japonica JAPANESE CEDAR Regular Regular Regular

Cupaniopsis anacardioides CARROTWOOD Minimal None None

Cupressocyparis leylandii LEYLAND CYPRESS Regular Regular Regular

Cupressus macrocarpa MONTEREY CYPRESS Moderate – Minimal None Minimal

Cupressus sempervirens ITALIAN CYPRESS Minimal Minimal Minimal

Cupressus spp. CYPRESS Minimal Minimal Minimal

Diospyros virginiana AMERICAN PERSIMMON Regular Regular Regular

Dodonaea viscosa HOPSEED Moderate – Minimal None Minimal

Dracaena draco DRAGON TREE Moderate Moderate Moderate

Duranta repens SKY FLOWER Regular Regular Regular

Eriobotrya deflexa BRONZE LOQUAT Regular Regular Regular

Eriobotrya japonica EDIBLE LOQUAT Regular Regular Regular

Erythrina bidwillii BIDWILLS CORAL TREE Regular Regular Regular

Erythrina caffra KAFFIRBOOM CORAL TREE Regular Regular Regular

Erythrina coralloides NAKED CORAL TREE Regular Regular Regular

Erythrina crista-galli COCKSPUR CORAL TREE Regular Regular Regular

Erythrina spp. CORAL TREE Regular Regular Regular

Eucalyptus camaldulensis RED GUM Minimal None Minimal Eucalyptus cinerea ASH GUM Minimal None Minimal

Eucalyptus citriodora LEMON-SCENTED GUM Minimal None Minimal

Eucalyptus cladocalyx SUGAR GUM Minimal None Minimal

Eucalyptus cornuta YATE Minimal None Minimal

Eucalyptus ficifolia RED FLOWERING GUM Minimal None Minimal

Eucalyptus globulus BLUE GUM Minimal None Minimal

Eucalyptus grandis FLOODED GUM Minimal None Minimal

Eucalyptus leucoxylon WHITE IRONBARK Minimal None Minimal

Eucalyptus maculata SPOTTED GUM Minimal None Minimal NICHOL'S WILLOW LEAFED Eucalyptus nicholii Minimal None Minimal PEPPERMINT Eucalyptus polyanthemos SILVER DOLLAR GUM Minimal None Minimal

Eucalyptus rudis DESERT GUM Minimal None Minimal

Eucalyptus sideroxylon RED IRONBARK Minimal None Minimal

Eucalyptus spp. EUCALYPTUS Minimal None Minimal

Eucalyptus torquata CORAL GUM Minimal None Minimal

Eucalyptus viminalis MANNA GUM Minimal None Minimal

Euphorbia cotinifolia CARIBBEAN COPPER TREE Minimal None Minimal

Feijoa sellowiana PINEAPPLE GUAVA Regular Regular Regular

Ficus 'Alii' FICUS ALII Regular Regular Regular

Ficus benjamina WEEPING FIG Regular Regular Regular

Ficus carica EDIBLE FIG Regular Regular Regular

Ficus elastica RUBBER TREE Regular Regular Regular

Ficus macrophylla MORETON BAY FIG Regular Regular Regular

Ficus microcarpa WEEPING INDIAN LAUREL FIG Regular Regular Regular GREEN GEM INDIAN LAUREL Ficus microcarpa 'Green Gem' Regular Regular Regular FIG Ficus microcarpa 'Nitida' INDIAN LAUREL FIG Regular Regular Regular

Ficus rubiginosa RUSTY LEAF FIG Regular Regular Regular

Ficus spp. FIG Regular Regular Regular

Ficus watkinsiana WATKINS FIG Regular Regular Regular

Fraxinus uhdei SHAMEL ASH Moderate – Minimal None Minimal

Fraxinus uhdei 'Tomlinson' TOMLINSON ASH Moderate – Minimal None Minimal

Fraxinus velutina ARIZONA ASH Moderate – Minimal None Minimal

Fraxinus velutina 'Dr Pironne' ASH ARIZONA Moderate – Minimal None Minimal

Fraxinus velutina 'Modesto' MODESTO ASH Moderate – Minimal None Minimal

Geijera parviflora AUSTRALIAN WILLOW Moderate – Minimal None Minimal

Ginkgo biloba MAIDENHAIR TREE Moderate – Minimal Moderate – Minimal Moderate – Low

Ginkgo biloba 'Autumn Gold' GINKGO AUTUMN GOLD Moderate – Minimal Moderate – Minimal Moderate – Low Grevillea robusta SILK OAK Minimal None Minimal

Hakea laurina PINCUSHION TREE None None None

Harpephyllum caffrum KAFFIR PLUM Moderate – Minimal Moderate – Minimal Moderate – Low

Hymenosporum flavum SWEETSHADE Moderate Moderate Moderate

Jacaranda mimosifolia JACARANDA Moderate – Minimal Minimal - None Minimal

Juglans hindsii CALIFORNIA BLACK WALNUT None None None

Juniperus chinensis CHINESE JUNIPER Minimal Minimal None

Juniperus chinensis 'Torulosa' HOLLYWOOD JUNIPER Minimal Minimal None

Juniperus spp. JUNIPER Minimal Minimal None

Koelreuteria bipinnata CHINESE FLAME TREE Moderate Moderate Minimal

Koelreuteria paniculata GOLDENRAIN TREE Moderate Moderate Minimal

Lagerstroemia indica CRAPE MYRTLE Moderate – Minimal Young trees only None Lagerstroemia indica CRAPE MYRTLE Moderate – Minimal Young trees only None 'Muskogee' Lagerstroemia indica CRAPE MYRTLE TUSCARORA Moderate – Minimal Young trees only None 'Tuscarora' Lagunaria patersonii PRIMROSE TREE Moderate – Minimal Moderate – Minimal None

Laurus nobilis SWEET BAY Moderate – Minimal Moderate – Minimal None

Leptospermum laevigatum AUSTRALIAN TEA TREE Moderate – Minimal Moderate – Minimal None

Leptospermum spp. TEA TREE Moderate – Minimal Moderate – Minimal None

Leucaena glauca WHITE POPINAC Moderate – Minimal Moderate – Minimal None

Liquidambar orientalis ORIENTAL SWEETGUM Moderate Moderate Moderate

Liquidambar styraciflua AMERICAN SWEETGUM Moderate Moderate Moderate Liquidambar styraciflua BURGUNDY SWEETGUM Moderate Moderate Moderate 'Burgundy' Liquidambar styraciflua ROUND-LEAFED SWEETGUM Moderate Moderate Moderate 'Rotundiloba' Liriodendron tulipifera TULIP TREE Regular Regular Regular

Lophostemon confertus BRISBANE BOX Minimal None None FERN-LEAF CATALINA Lyonothamnus floribundus Moderate – Minimal Moderate – Minimal Minimal IRONWOOD Macadamia tetraphylla ROUGH-SHELL MACADAMIA Regular Regular Regular

Magnolia grandiflora SOUTHERN MAGNOLIA Moderate Moderate Minimal Magnolia grandiflora 'Samuel MAGNOLIA SAMUEL SOMMER Moderate - Regular Moderate -Regular Moderate -Regular Sommer' Malus sylvestris EDIBLE APPLE Moderate - Regular Moderate -Regular Moderate -Regular

Maytenus boaria MAYTEN TREE Moderate - Regular Moderate - Regular Moderate - Regular

Melaleuca armillaris DROOPING MELALEUCA Minimal None None

Melaleuca ericifolia HEATH MELALEUCA Minimal None None

Melaleuca nesophila PINK MELALEUCA Minimal None None

Melaleuca quinquenervia CAJEPUT TREE Minimal None None NEW ZEALAND CHRISTMAS Metrosideros excelsus Minimal Young trees only None TREE Morus alba WHITE MULBERRY Regular Regular Regular Musa spp. BANANA Ample Ample Ample

Myoporum laetum MYOPORUM Minimal - None Minimal - None None

Myrtus communis TRUE MYRTLE Moderate – Minimal Moderate – Minimal Low

Neodypsis decaryi TRIANGLE PALM Regular Regular Regular

Nerium oleander OLEANDER Minimal None None

Olea europaea OLIVE Minimal None None

Persea americana AVOCADO Regular Regular Regular

Persea borbonia RED BAY Regular Regular Regular

Phoenix canariensis CANARY ISLAND DATE PALM Moderate – Minimal None None

Phoenix dactylifera DATE PALM Regular Regular Regular

Phoenix loureri DATE PALM Regular Regular Regular

Phoenix reclinata SENEGAL PALM Regular Regular Regular

Phoenix roebelenii PYGMY DATE PALM Regular Regular Regular

Pinus brutia CALABRIAN PINE Minimal Young trees only None

Pinus canariensis CANARY ISLAND PINE Minimal Young trees only None

Pinus densiflora JAPANESE RED PINE Minimal Young trees only None

Pinus edulis PINON PINE Minimal Young trees only None

Pinus halepensis ALEPPO PINE Minimal Young trees only None

Pinus pinaster CLUSTER PINE Minimal Young trees only None

Pinus pinea ITALIAN STONE PINE Minimal Young trees only None

Pinus radiata MONTEREY PINE Minimal Young trees only None

Pinus thunbergiana JAPANESE BLACK PINE Minimal Young trees only None

Pinus torreyana TORREY PINE Minimal Young trees only None

Pistacia chinensis CHINESE PISTACHE Minimal - None Minimal - None None

Pittosporum crassifolium KARO Moderate Moderate Minimal

Pittosporum phillyreoides WILLOW PITTOSPORUM Moderate Moderate Minimal

Pittosporum rhombifolium QUEENSLAND PITTOSPORUM Moderate Moderate Minimal

Pittosporum spp. PITTOSPORUM Moderate Moderate Minimal

Pittosporum tobira MOCK ORANGE Moderate Moderate Minimal

Pittosporum undulatum VICTORIAN BOX Moderate Moderate Minimal

Pittosporum viridiflorum CAPE PITTOSPORUM Moderate Moderate Minimal

Platanus acerifolia LONDON PLANE Moderate Moderate Moderate

Platanus acerifolia 'Bloodgood' LONDON PLANE BLOODGOOD Moderate Moderate Moderate

Platanus occidentalis AMERICAN SYCAMORE Moderate Moderate Moderate

Platanus racemosa CALIFORNIA SYCAMORE Moderate Moderate Moderate

Platycladus orientalis ORIENTAL ARBORVITAE Moderate Moderate Minimal

Podocarpus gracilior FERN PINE Regular Regular Regular Podocarpus henkelii LONG-LEAFED YELLOWWOOD Regular Regular Regular

Podocarpus macrophyllus YEW PINE Minimal Minimal Minimal

Podocarpus nagi PODOCARPUS NAGI Regular Regular Regular

Populus alba WHITE POPLAR Regular Regular Regular

Populus nigra 'Italica' LOMBARDY POPLAR Regular Regular Regular

Prunus amygdalus ALMOND Moderate - Regular Moderate - Regular Moderate - Regular

Prunus armeniaca APRICOT Moderate - Regular Moderate - Regular Moderate - Regular

Prunus blireiana FLOWERING PLUM Moderate - Regular Moderate - Regular Moderate - Regular

Prunus caroliniana CAROLINA LAUREL CHERRY Moderate - Regular Moderate - Regular Moderate - Regular

Prunus cerasifera PURPLE-LEAF PLUM Moderate - Regular Moderate - Regular Moderate - Regular

Prunus domestica PLUM Moderate - Regular Moderate - Regular Moderate - Regular

Prunus lyonii CATALINA CHERRY Moderate - Regular Moderate - Regular Moderate - Regular

Prunus 'Mt Fuji' CHERRY MT FUJI Moderate - Regular Moderate - Regular Moderate - Regular

Prunus persica PEACH Moderate - Regular Moderate - Regular Moderate - Regular JAPANESE FLOWERING Prunus serrulata Moderate - Regular Moderate - Regular Moderate - Regular CHERRY Psidium cattleianum STRAWBERRY GUAVA Regular Regular Regular

Pyrus calleryana ORNAMENTAL PEAR Moderate Moderate Moderate

Pyrus communis FRUITING PEAR Moderate Moderate Moderate

Pyrus kawakamii EVERGREEN PEAR Moderate Moderate Moderate

Quercus agrifolia COAST LIVE OAK Minimal None Minimal - None

Quercus ilex HOLLY OAK Minimal None Minimal - None

Quercus suber CORK OAK Minimal None Minimal - None

Quercus virginiana SOUTHERN LIVE OAK Minimal None Minimal - None

Radermachera sinica CHINA DOLL Regular Regular Regular

Ravenea rivularis MAJESTY PALM Regular Regular Regular

Roystonea oleracea SOUTH AMERICAN ROYAL PALM Regular Regular Regular

Roystonea regia CUBAN ROYAL PALM Regular Regular Regular

Salix matsudana 'Tortuosa' CORKSCREW WILLOW Regular Regular Regular

Schefflera actinophylla QUEENSLAND UMBRELLA TREE Regular Regular Regular

Schinus molle CALIFORNIA PEPPER Minimal Minimal None

Schinus terebinthifolius BRAZILIAN PEPPER Minimal None None

Sequoia sempervirens COAST REDWOOD Ample Ample Ample

Sequoiadendron giganteum GIANT SEQUOIA Ample Ample Ample

Stenocarpus sinuatus FIREWHEEL TREE Moderate Moderate Moderate

Strelitzia nicolai GIANT BIRD OF PARADISE Moderate Moderate Moderate

Syagrus romanzoffianum QUEEN PALM Moderate Moderate Minimal

Syzygium paniculatum BRUSH CHERRY Moderate Moderate Moderate Tabebuia chrysotricha GOLDEN TRUMPET TREE Regular Regular Regular

Taxodium mucronatum MONTEZUMA CYPRESS Minimal - None Minimal - None None

Thevetia peruviana YELLOW OLEANDER Minimal None Minimal

Tipuana tipu TIPU Regular Regular Regular

Trachycarpus fortunei WINDMILL PALM Regular Regular Regular

Tristaniopsis laurina WATER GUM None None None

Tupidanthus calyptratus TUPIDANTHUS Regular Regular Regular

Ulmus parvifolia CHINESE ELM Regular Regular Regular

Ulmus parvifolia 'Drake' DRAKE ELM Regular Regular Regular

Ulmus pumila SIBERIAN ELM Regular Regular Regular

Umbellularia californica CALIFORNIA BAY Minimal - None Minimal - None None

Viburnum tinus LAURUSTINUS Regular Regular Regular

Washingtonia filifera CALIFORNIA FAN PALM Minimal - None Minimal - None None

Washingtonia robusta MEXICAN FAN PALM Minimal - None Minimal - None None

Wodyetia bifurcata FOXTAIL PALM Moderate - Regular Moderate - Regular Moderate - Regular

Xylosma congestum XYLOSMA Moderate Moderate Moderate

Yucca elephantipes GIANT YUCCA Minimal - None Minimal - None None

Yucca gloriosa SPANISH DAGGER Minimal - None Minimal - None None

Yucca spp. YUCCA Minimal - None Minimal - None None

Department of Public Works 1685 Main Street Santa Monica CA 90401

Parkway Landscaping Policy for the City of Santa Monica Rev 6: 02/01/10

1. Background Parkways, the area between the outside edge of the sidewalk and the inside edge of the curb (if any), are a component of the Public Right of Way (PROW). The City is required to regulate activities within the PROW such as telephone equipment, street lighting, bus stops and parking meters. Adjacent property owners are required to maintain parkways in good order according to the Santa Monica Municipal Code and other City policies. Parkways present a number of challenges. There are issues of personal safety, vehicle safety, efficient access for pedestrians and vehicles and resource conservation. The purpose of this document is to establish a City policy on landscaping within parkways that takes into consideration these, sometimes competing, interests while allowing property owners to create attractive, useful frontages.

2. Applicability This policy applies to new construction of any type in all parkways of the City of Santa Monica. For the purposes of this Policy “new construction” is defined as modification or improvement of landscaping and/or irrigation, in 50% or more of the parkway area exclusive of tree roots and existing accessways (carriage walks).

3. Permits An Encroachment Permit from the Administrative Services Division of the City’s Environmental and Public Works Management Department is required for demolition and/or construction of any kind in parkways of the City with the exception of the installation of unirrigated, walkable plant materials such as those described in Appendix B. Permits and plan approvals issued by the Division of Building and Safety are not applicable to parkways.

4. Basic Recommended Approach Attractive landscaping using a mixture of permeable paving and climate-appropriate plants that provides vehicle operators safe access to and from off-street parking and pedestrians safe use of the sidewalk as well as access to and from vehicles parked at the curb. This landscaping should require little or no irrigation and produce no runoff.

5. Safety Parkway landscaping must not create visual obstructions for pedestrians or drivers of vehicles. See Santa Monica Municipal Code (SMMC) Section 9.04.10.02.090 for specific criteria. Parkway Landscaping Policy Revision 6: 02/01/10 2

6. Step-Out Strips A step-out strip (a uniform, firm walking surface from the curb edge inward) must be provided for passengers to enter and exit vehicles parked at the curb. Step-out strips must be at least 18 inches in width and at least 36" long, provide a firm, uniform walking surface in all weather conditions and extend the full length of the parkway. Exception: Step-out strips are not permitted adjacent to red curbs or where roots of existing street trees make construction of a step-out strip with the required dimensions impossible or impractical (See Section 11). Additional step-out strips may be provided adjacent to driveway aprons as desired.

7. Accessways (Carriage Walks) If desired, the landscape design of a parkway may include an accessway for the purpose of pedestrian access to vehicles parked at the curb. If included, accessways must be at least four feet in width and provide a firm, uniform walking surface in all weather conditions from the curb to the sidewalk. Exception: Accessways are not permitted adjacent to red curbs or where construction of the accessway would damage or negatively impact the roots of existing street trees. (See Section 11).

8. Areas of Limited Access All portions of the parkway other than step-out-strips and accessways are considered Areas of Limited Access (ALA). Landscaping in ALAs may be composed of plant material or other features except where construction of such features would damage or negatively impact the roots of existing street trees. (See Section 11).

Figure 1 - Parkway Components Parkway Landscaping Policy Revision 6: 02/01/10 3

9. Construction Criteria A. Step-Out Strips and Accessways Step-out strips and accessways may be constructed of pavement, or plant material*. Permeable paving such as unstabilized decomposed granite (DG) is preferred. Stabilized DG, if used, will not be considered permeable in parkways governed by this policy. Any form of DG, if used, must be constructed according to Appendix A.

B. Areas of Limited Access ALAs may include trees** and other materials such permeable paving, boulders or constructed objects and plants; not to exceed 34 inches in height. Native and/or Mediterranean plants requiring little or no irrigation are preferred. See SMMC 9.04.10.02.090 for specific criteria on plant placement and dimensions. A 2" to 4" layer of organic mulch is recommended in planting beds and under trees. More than four inches may inhibit the growth of plants and street trees. To avoid harm to street trees, do not place mulch within 24 inches of tree trunks. See SMMC 9.04.10.02.090 for criteria on placement and dimensions of landscape features.

C. Grading and Drainage There must be no difference in grade where pavement within parkways meets adjacent surfaces such as the curb top, sidewalk or driveway apron. Grade changes on step-out strips are limited to ¼” per foot. Grade changes on accessways are limited to ¼” per foot or the difference in elevation between the sidewalk and the top of the curb. If impermeable surfaces are used within parkways, they must be constructed to drain to permeable areas.

* See Appendix B for a list of suggested plants. Use of plants on this list is not required. NOTE: Irrigation restrictions may influence your plant choices. See Section 10 below. ** Trees in Santa Monica's parkways are under the supervision of the City's Community Forester. Before adding or modifying trees in the parkway, review the City’s Community Forest Management Plan at http://www.smgov.net/Trees/Mgmt Plan/Complete.pdf or call the Community Forester at 310/458-8974.

10. Irrigation Permanently installed irrigation of plant material in parkways is not required. Low-volume, non-spray irrigation systems or hand-watering is preferred where irrigation is needed. Irrigation systems in parkways must be designed and constructed in a manner to completely preclude overspray and runoff onto any impermeable surface, public or private, under any condition with no exception for the effects of wind. See SMMC 7.16.020 c3 & 7.10.040 a1and SMMC 8.108 Subpart B. Parkway Landscaping Policy Revision 6: 02/01/10 4

No spray irrigation device of any type may be installed within 24” of any impermeable surface or trees. See Figure 2, below. The planned coverage area of spray irrigation systems in parkways may not include any area within 24” of any impermeable surface or trees. See Figure 2, below. All irrigation equipment in parkways including heads, valves, piping, tubing and control wire must be installed in accordance with SMMC 8.32 and SMMC 8.108 Subpart B. When installing an irrigation system, it is important not to damage the roots of any existing street trees. In some cases the roots of a street tree may occupy all or a large portion of the parkway making installation of an irrigation system impractical. See example below.

24”

24”

24”

Figure 2 – Limits of Sprinkler Irrigation in Parkways 11. Street Trees Landscaping and irrigation in parkways must be designed in a manner that does not endanger the health of existing street trees. The layout of step-out strips and accessways in particular must be constructed in a manner that avoids interference with the existing trunk flare or roots of these trees. See examples in Figures 3 – 9 below. It is important to understand that, in some cases, surface roots of street trees may make landscaping, accessways, step-out strips and/or irrigation impractical or even impossible. When in doubt, review the City’s Community Forest Management Plan at http://www.smgov.net/Trees/Mgmt Plan/Complete.pdf or contact the Community Forester.

In some cases the roots of a street tree may occupy the entire parkway precluding the installation of an irrigation system. Landscaping or irrigation in the parkway shown at left would be detrimental to the tree.

Figure 3 – Parkway width in relation to street trees

Parkway Landscaping Policy Revision 6: 02/01/10 5

Step-out strip does not interfere with tree.

Figure 4 – Step-out strip in relation to tree

Exposed roots at the edge of parkway preclude installation of a Step-out strip or accessway.

Figure 5 – Step-out strip in relation to tree roots Parkway Landscaping Policy Revision 6: 02/01/10 6

The irregular root systems found above the soil surface in some parkways are crucial to tree stability and provide limited areas for step-out strips. An accessway would not be permitted here.

Figure 6 – Above-grade roots

≥24” Maintain a clear zone of at least 24” around the base of the trunk to avoid crown rot and damage from line trimmers

Figure 7 – Clearance from trees Parkway Landscaping Policy Revision 6: 02/01/10 7

Figure 8 Do not plant shrubs Figure 9 The photo above shows an and flowers around the base of effective use of mulch with no plants trees. They rob newly planted at the base of the trunk of the tree. trees of nutrients and moisture. Plants that surround the trunk flare of mature trees create conditions for crown rot which can ultimately lead to the decline and failure of the tree.

12. Maintenance Responsibility Maintenance of parkways is the responsibility of the adjacent property owner. See SMMC 9.04.10.04.100j.

13. For questions regarding: Plan review and permits for parkways: Contact Public Works Administrative Services at [email protected] or 310 / 458-8737 Landscaping and irrigation in parkways: Contact the Office of Sustainability and the Environment at [email protected] or 310 / 458-8972 Trees in parkways: Contact the City’s Community Forester at [email protected] or 310 / 458-8974 Parkway Landscaping Policy Revision 6: 02/01/10 8

Appendix A Specification for Installation of Unstabilized Decomposed Granite (DG) Paving

MATERIALS Base Course Aggregate: ASTM C33, crushed stone or crushed gravel.

Decomposed Granite: 1. Clean, hard, durable particles or fragments of ¼” minus fines, select brown/gray crushed granite, river rock or basalt. Fines shall be evenly mixed throughout the aggregate. When produced from gravel, 50 percent, by weight, of the material retained on a No. 4 sieve shall have one fractured face. Color to be California Gold, Brimstone or Architect approved equal.

2. The portion retained on the No. 4 sieve shall have a maximum percentage of wear of 50 at 500 revolutions as determined by AASHTO T96-77.

3. The portion passing a No. 4 sieve shall have a maximum liquid limit of 25 and a maximum plasticity index of 7, as determined by AASHTO T89-81, and AASHTO T90-81, respectively.

4. The crushed aggregate screenings shall be free from clay lumps, vegetable matter, and deleterious material.

PREPARATION FOR INSTALLATION

Surface Preparation: Do necessary final excavating and filling to prepare finished subgrade. Building up of subgrade under forms after they are in place will not be permitted. After forms are in place, test subgrade with template, reduce high spots to grade and raise low spots to grade with materials compacted in place by tamping.

Decomposed Granite: 1. Subgrade preparation: Prior to placing the DG, shape, fill, grade, and compact the subgrade (crushed aggregate base).

2. Forms: Install adjacent paving in lieu of forms, the full depth of decomposed granite area, curving as required, and secure in place to hold firmly to and grade required.

If stabilizer is to be used, modify these instructions according to the manufacturers specifications. If stabilizer is used, decomposed granite paving will be considered an impermeable surface in parkways governed by this policy. Parkway Landscaping Policy Revision 6: 02/01/10 9

Appendix A cont’d

INSTALLATION

Base Course 1. Construct a base course layer to a depth of 4 inches (compacted). Deposit aggregate directly on prepared subgrade or preceding layer of compacted aggregate. Keep placed material free from segregation. Compact each layer of material with tamping roller, with pneumatic tired roller, with vibration machine, or with combination of the three.

2. If subgrade material is worked into base course material during compacting or finishing operations, remove base course material within affected area and replace with new aggregate. Restrict hauling over completed or partially completed work when subgrade is soft or there is tendency for subgrade material to work into base course material.

3. Compact each layer with aid of water. Provide sufficient moisture to prevent segregation into pockets of fine and coarse material.

Decomposed Granite (DG) 1. Place the DG on the prepared subgrade, in one layer of three inches minimum thickness and rake smooth using a steel tine rake to desired grade and cross section. Do not apply DG deeper than 3 inches.

2. Water to achieve full depth moisture penetration. Watering is best accomplished using a garden hose with spray nozzle set to a coarse spray; pressure should not disturb leveled surface. It is essential that the full depth of water penetration by random inspection of cores. After inspection, fill core holes with material removed, smooth and hand tamp to match adjoining trail surface grade. Let watered mix stand 6 to 24 hours until surface water is no longer present; the mix should then be moist but not wet.

3. While the mix is still thoroughly moist, roll with a heavy lawn roller (minimum 225 pounds and maximum 30-inch width), to achieve finish grade and initial compaction. Hand tamp edges around poles, and other objects. Use a heavy (1 ton minimum) small rider, after having initially used the lawn roller, to obtain the desired final dense, smooth, uniform texture. Do not use wackers or vibratory rollers; the mix will not harden for weeks after vibration.

4. Landscape header or curb is to remain in place, secured to hold firmly to approved line and grade. After finished compacted surface has been achieved, finish adjacent shoulders by backfilling required grade and cross section.

INSPECTION 1. Finished surface shall be smooth and uniform with no evidence of chipping or cracking. Dried, compacted material shall be firm all the way through with no spongy areas.

2. Significant irregularities shall be smoothed out prior to final acceptance of work. Smoothing shall be accomplished by rewetting/saturating rough areas thoroughly, and then rolling the surface again with a heavy roller (1,000 to 1,500 lbs powered walk- behind or small rider). Wackers are not recommended. Parkway Landscaping Policy Revision 6: 02/01/10 10

3. Final thickness of completed area shall not vary more than ½ inch from dimension indicated. Measurements may be taken by means of test holes taken at random in the finished surface. Correct any variations in the thickness beyond the allowable ½ inch by repeating the procedures listed above.

Appendix B – Suggested Plants Use of plants on this list is not required. Plants for Accessways and Step-Out Strips Dymondia margaretae

Plants for Areas of Limited Access Carex spp. Also see http://www.bewaterwise.com/Gardensoft/browser01.aspx Also go to http://www.sustainablesm.org/landscape look under “Plants and Soil” – See the Lawn Alternatives document