Ground Covers 225 contain organic matter, such as well- rotted manure, compost, or peat moss. Work it in well before you . Water should be available in order to get the ofT to a good start and to prevent them from suffering during dry periods. Ground The planting can be done in the spring or the fall, according to the general practice in your area. Fall Covers planting often is satisfactory if it is done early enough to allow the young plants to become established thoroughly before the ground freezes. GRASS is the best of all the ground Spring planting may be better in covers. It can be walked on, played many sections. on, and trampled on frequently, yet To space the individual plants it remains an excellent cover for the properly at planting time, you should ground if it is fertilized, watered, cut know the growth rate of the plants regularly, and weeded occasionally. you select and decide whether you Some other plants withstand a cer- want a complete ground cover the tain amount of pedestrian traffic, but first season or whether you can wait grass still is the most serviceable of all. a few years until the plants eventually Many gardeners look for other grow together. ground-covering plants that require For instance, the honeysuckles and little or no care. Trees and shrubs the memorial rose grow rapidly, and that grow with branches touching the individual plants may be expected ground do well in certain situations. to cover several square feet during Annual and perennial flowering plants the first year. will suffice in other places. Other plants, like the European If you want other plants in order wild ginger, grow slowly, and it may to make a planting more interesting be several years before plants spaced or to avoid the care that grass needs, a foot apart will grow together. you should consider certain factors Evergreens, such as some of the before you choose a specific plant: creeping junipers, are expensive com- Is the site in the sun or the shade? pared to small herbaceous plants, Is the soil poor and dry or medium yet an individual evergreen may to good? cover 4 square feet when you buy it. Do you want evergreen plants? Large clumps of herbaceous plants How high is the ground cover to may be bought and pulled apart at be—a few inches or a foot or more? the time of planting to cover as Need the ground cover be serviceable much space as possible. With certain all year, or can it be an herbaceous exceptions, it is well to allow about one, which dies to the ground in the 2 square feet of space for each of late fall, leaving the ground bare and the herbaceous plants generally used ostensibly lacking in plant material as ground covers. during the winter? One of the purposes of ground-cover Those questions are important. Once plants is to help prevent soil erosion. you have made your decisions respect- All plants prevent erosion to some ing them, it is much easier to select extent, but fast-growing vines and the proper plant as a ground cover for shrubs that root readily along the the area. branches that touch the soil are better Careful preparations should be taken to use in such situations than are in the planting. The ground should herbaceous perennials, which die to 748-092 °—65 1& 226 The Yearbook of Agriculture 1965 the ground in winter and give little Peat moss, wood chips, pine needles, protection to the soil in early spring, ground sugarcane stalks, ground bark when melting snows cause the worst of almost any kind, ground corn- erosion. cobs—any such material aids in con- Give careful thought to ways to serving the moisture in the soil and prevent erosion at planting time. One reducing weed growth, but none of method is to terrace the bank and them should be applied more than 2 planting slightly in such a way that the inches deep. runners of the vines go at right angles In northern regions, one must watch to the slope. Also, you can sink boards for the heaving of small plants in the at right angles to the slope; let them early spring. Heaving is brought about protrude a few inches above the soil, during the late winter and early spring and keep them in. place for the first by warm, sunny weather alternating year or two until the plants become with freezing temperatures. Govering established. a young planting with evergreen Mulching with hay or straw helps boughs, burlap, or hay the first prevent runoff for the first year or winter helps to prevent the heaving of two. Placing large wire hairpins over small plants. Replanting of heaved the stems of the plants to keep them in plants should be done immediately. place on the soil surface may encour- Pruning a planting of ground cover age rapid rooting, especially if you put sometimes is necessary to aid the plants a shovelful of soil over the stem to keep in becoming bushy and dense. Some- the branch moist. times a shrub may grow too vigor- In any event, select healthy, vig- ously and need to be reduced to orous-growing woody plants for this conform with the rest of the planting. type of planting. We do this occasionally with the Among such plants are the dwarf fragrant sumac or Arnold Dwarf bush honeysuckle {Diervilla lonicera) ^ Forsythia merely to make the planting Arnold Dwarf Forsythia, English ivy more uniform in appearance. {Hederá helix) ^ varieties of creeping Certain plants, like the yarrow, can juniper {Juniperus horizonmlis), Henry even be mowed if necessary with a honeysuckle {Lonicera henry i) ^ Hall's reel-type or rotary-blade mower. You honeysuckle {Lonicera japónica halliana), could also use a brush scythe on some dwarf Japanese fleeceflower {Poly- of the woody ground covers if its use gonum cuspidatum 'Gompactum'), fra- will improve the general appearance grant sumac {Rhus aromática)^ and of the planting. memorial rose {Rosa wichuraiana). A few here and there in a low Some of these rapid-growing ground ground cover create a color contrast covers, like the HalFs honeysuckle and during the early spring. the dwarf Japanese fleeceflower, can become pests in good soil, unless they To SELECT the best possible plant as a are rigidly restrained. ground cover for a specific situation, If you select the right plant for the one must consider the extremes of situation, maintenance will be reduced winter and summer temperatures, the to a minimum. It is always well, when amount of rainfall, and the vagaries of possible, to add mulch just after the the site itself. plants have been set in the ground. A few suggestions of some of the bet- The mulch keeps the soil moist about ter ground covers for specific situations the young plants and aids in their are noted in the following lists. An rooting. It helps control weeds. asterisk in front of the name indicates An application of fertilizer can help bardine^ in the colder parts of north- after the plants are started, but of the em New England and the northern two things, the mulching is the more Great Plains States. Specific notes on important. hardiness of the other plants should be Ground Covers 227 noted in standard reference books, but Tiarella cordijolia (Alleghany foam- all are grown as ground covers in flower), Vinca minor (periwinkle). gardens throughout the United States. (DONALD WYMAN) Ground Covers for Dry Soils

*Aegopodium podograria (goutweed), Ground Covers That Increase Rapidly ^Coronilla varia (crownvetch), Genista pilosa (silky- woadwaxen), "^Hosta *Aegopodium podograria (goutweed), species (plantain-lilies), Hypericum calyc- Ajuga reptans (bugleweed), "^Convallaria inum (Aarons-beard St. Johnswort), majalis (lily-of-the-valley), Forsythia * Juniperus species (junipers), *Phalaris * Arnold Dwarf,' Lonicera japónica hal- arundinacea picta (ribbongrass), Poly- liana (Hall's honeysuckle), "^Phalaris gonum species (fleeceflowers), "^Rhus arundinacea picta (ribbongrass), Poly go- aromática (fragrant sumac), ^Vaccinium num cuspidatum 'Compactum' (dwarf angustifolium laevifolium (lowbush blue- Japanese fleeceflower), Rosa wichurai- berry). ana (memorial rose), Sasa species (hardy bamboos). Vinca minor (peri- Ground Covers Jor Wet Soil winkle) . Asarum caudatum (British Columbia Evergreen Ground Covers wildginger), Asperula odorata (sweet woodruff), Galax aphylla (galax), ^Ge- "^Arctostaphylos uva-ursi (bearberry), ranium sanguineum prostratum (dwarf Euonymus fortunei varieties (winter- blood red geranium), "^Hasta species creeper), Galax aphylla (galax). Gay- (plantain-lilies), ^Lysimachia nummu- lussacia br achy cera (box huckleberry), laria (moneywort), Myosotis scorpioides Hederá helix (English ivy), ^Juniperus (true forget-me-not), "^Phlox divaricata species (junipers), Mahonia species (wild sweet-william), Veronica repens (holly grape), Pachysandra terminalis (creeping speedwell), Xanthorhiza sim- (Japanese pachysandra), '^Thymus ser- plicissima (yellowroot). pyllum (mother-of-thyme), Vinca rhinor (periwinkle). Ground Covers Jor Seashore

Flowering Ground Covers "^Arctostaphylos uva-ursi (bearberry), "^Artemesia stelleriana (beach worm- Ajuga reptans (bugleweed), Calluna wood), Calluna vulgaris (Scotch heath- vulgaris (Scotch heather), Cytisus spe- er), ^Campanula species (bellflowers), cies (brooms), Erica species (spring *Cerastium tomentosum (snow-in-sum- heaths), Helianthemum nummularium mer), *Comptonia peregrina (sweetfern), (sunrose), ^Hosta species (plantain- Cytisus species (brooms), Juniperus con- lilies), Hypericum species (St. Johns- ferta (shore juniper), Rosa wichuraiana worts), Lonicera species (honeysuckles), (memorial rose)^^Vaccinium -idaea "^Phlox species (phlox), ^Rosa species minus (mountain cranberry). (roses). Ground Covers That May Be Cut With a Ground Covers Jor Shade Lawnmower

Ajuga reptans (bugleweed), '^Aegopo- ^Aegopodium podograria (goutweed), dium podograria (goutweed), Asarum spe- Hypericum repens (creeping St. Johns- cies (wildgingers), "^Epimedium species wort), ^Lysimachia nummularia (money- (epimediums), Hederá helix (English wort), reptans (mazus), ^Nepeta ivy), ^Hosta species (plantain-lilies), hederacea (ground-ivy), ^Potentilla tri- Pachysandra terminalis (Japanese pachy- dentata (wineleaf cinquefoil), "^Prunella sandra), A'ûi'â! species (hardy bamboos), vulgaris (self heal). "^ Thymus species 228 The Yearbook of Agriculture 1965 (thyme), Veronica species (speedwelk), mid areas (carpet, zoysia, centipede ^ Vio la species (violets). St. Augustine, and bermudagrasses); and grasses for the dryland area of Ground Covers for Warm Areas of Gulf the Great Plains (crested wheat, blue Coast and Pacific Coast grama, and buffalograsses). Temperature and moisture largely Gazaniasecies (South African daisy), determine the adaptation of grass. Hypericum calycinum (Aarons-beard St. In general, the best time to seed or Johiîswort), Mesembrjanthemum species plant cool-season grasses is in the fall or (ice plants), Lippia camscens repens early spring. (creeping lippia), Ophiopogon japonicum Warm-season grasses are planted in (mondograss), Pelargonium peltatttm the spring or early summer. (ivy-vine pelargonium), Santolina cham- aecyparissus (cypress lavender-cotton), A POORLY COLORED, thin, or weedy Saxífraga sarmentosum (strav^berry saxi- lawn is a hungry lawn. frage), Sedum species (sedums), Verbena Nutrients that grass plants need in peruviana varieties (Peruvian verbena). large amounts are nitrogen, phos- phorus, and potassium. They are listed as N, P, and K on all fertilizer bags, in that order, with the percentage of each. Many kinds and ratios of fertilizers are suitable for lawns. Choose one whose first—^nitrogen (N)—^number is as large or larger than the amounts of Lawns P and K. For example, a 10-6-4 ferti- lizer contains 10 percent nitrogen, € percent phosphorus, and 4 percent potassium. You DO NOT have to be an expert to The amount of fertilizer to apply to make and maintain a good lawn. Fol- lawns we calculate on the percentage low a few general principles. Avoid of nitrogen in the fertilizer. It is gener- hit-or-mi^ methods. ally recommended that not more than Some common causes of poor lawns I pound of actual nitrogen per i thou- are : The use of passes not suited to the sand square £e^t be applied at any one locality, too little or too much fertilizer, time. That would amount to 10 pounds improj^r mowing and watering, too of 10-6-4, 5 pounds of 20-10-5, 20 much shade, too much traffic, and pounds of 5-10-5, and so on per thou- poorly drainai or droughty soils. sand squaœ feet of lawn. Qhoowe a ^ass that is adapted to Grasses vary in their n^d for nitro- your locality and to the maintenance gen. A rough guide to the annual program you plan to follow. For ex- requirements is given in the table. ample, bentgrass lawns require fre- Too much fertilizer applied at any quent mowing, watering, fertilizing, one time may burn the grass and will and treatment with chemicals to kill overstimulate top growth and weaken fungi. If you do not want to expend the plant. You can reduce the danger labor and money for this kind of lawn, of burning by applying fertilizer when you should choose a grass that requires there is no moisture on the and less care. by watering immediately after you Three broad groups of lawn grasses apply the fertilizer. are: Organic types of fertilizer may be Cool-season grasses for cool, hunaid used in greater amounts than chemical areas (Kentucky biuegrass, red fsscue, types without burning the grass. tall fescue, and bentgrasses) ; Lawn grasses grow poorly in acid warm-season grasses for warm, hu- soils. Test your soil and apply ground