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Home , Grafting

5S? Universityof Idaho OCT

College of Current Information Series No. 532

Cooperative Extension Service April 1980 pAgricultural Experiment Station Propagating Ornamental and Shrubs A. A. Boef Professor, and T. J. Bakken, Research Assistant Department of and Soil Sciences

Commercial propagators have elaborate facilities — the trees and shrubs most commonly grown as orna for propagating trees and shrubs grown as ornamen mentals. The serious hobbiest can find more complete tals. These are necessary where the propagator must information in a number of good have a high percentage of success if he is to make a books. living. Definitions The home and hobbiestcan, however, do a tolerable job of propagating trees and shrubs with Here are definitions of some terms used in plant little or no equipment. The processes of rooting, graft propagation: union formation or seed germination might not be as Stratification — moist treatment of the seed, usually successful as in commercial facilities, but usually the at 40° F (4°C) but sometimes also at warmer tempera- hobbiest will only want a few of each kind. paper or with concentrated sulfuric acid. The rooting hormones can be purchased at garden Stratification — moist treatment of the seed, usually stores or a local nurseryman may have special concen at 40° F (4°C) but sometimes also at warmer temera- trations if needed. Bottom heat can be supplied by an tures. The seed is usually mixed with moist sand, ver- inexpensive heatingcable. Small shelters setup miculite or peat and placed in flats or plastic bags. in a shady part of the garden can substitute for the Hardwood cuttings — cuttings taken during the greenhouse environment. For summer or softwood cuttings, a lathhouse or even a shady spot will suffice. dormant season. Mist maybe applied by hand 3 or4timesa dayto keep Softwood cuttings — cuttings made from growing the cuttings turgid and cool. . Seeds may be collected and then stratifiedina home IBA — indole butyric acid, a used to refrigerator, or they may befall-planted to satisfy their induce rooting. It is usually formulated at various con cold requirement. Young may beshaded with centrations in talc. It may also be used as a liquid quick lath or snow fencing for the first few weeks. dip (concentrated) or soak (dilute) treatment. The publication summarizes methods of propagat Bottom heat — heating of the rooting media usually ing —byseed or by some form ofasexual propagation with electric cables.

Ornamental Trees and Shrubs

Genus Genus Propagation (Common name) Propagation (Common name) Seed —• Use fresh seed. Stratify I to 3 ripe. A palmatum seed will germinate Abies after being soaked overnight in hot water. (Fir) months at 40° F (4°C) or plant in the fall. Cuttings —Take in winter. Treat with .4% A. circinatum requires an extended strati or .8% IBA. Use bottom heat. fication period. -K Graft - Side-graft onto of same Cuttings —Summer cuttings ofA.ginnala species. and A. palmatum readily when 0 treated with .3% IBA. Use mist and bottom Acer Seed — Stratify at 40° F (4°C) for 90 days heat. Overwinter cuttings in a greenhouse

Acer (continued) when treated with 15 to 25 ppm IBA for 24 hours and placed in the greenhouse under Grafting — of the are mist. Root cuttings can be taken in the fall bud-grafted onto seedlings of the same and stored at 40° F (4°C) overwinter. They species. Grafting is done in late summer. are lined out in the field or potted in the Budded cultivars should be used in prefer spring. ence to seedling trees because of their uni Chamaecyparis Cuttings — Cultivars of C. lawsoniana are form growth habit. (False Cypress) hardy in most of Idaho. Cuttings root if Aescuhis Seeds — Gather seeds and stratify im treated with .3% IBA and benched from (Horsechestnut, mediately at 40° F (4°C). Field plant in August to February. Bottom heat aids Buckeye) rows or grow in 2 gallon containers. rooting. Cuttings placed in a cold frame in Alnus Seeds — Stratify at 40° F (4° C) for 60 to 90 fall will root readily the following spring. (Alder) days or field plant. Clematis Cuttings — The popular clematis vines are Arctostaphylos Seed — Try stratification for 3 to 4 months (Clematis) propagated by cuttings, usually taken from (Kinnickinnick, at 40° F (4°C). Germination will be erratic. greenhouse stock plants. Treat with .3% Bearberry) Cuttings — Take any time from August to IBA, or quick dip in 2000 to 4000 ppm, or March. Treat with .3% or .8% IBA. Use soak in 25 to 50 ppm for 12 to 24 hours. Use peat-sand, peat-perlite media and bottom mist and bottom heat. heat. Cornus Seed — Harvest berries when ripe, extract (Dogwood) seed and stratify immediately. If seed is Artemisia Cuttings — The artemisia used for orna (Sagebrush) mentals are propagated by cuttings which dry, as from commercial sources, soak 24 root easily when placed in a well-drained hours before stratifying. Stratify at 40° F but moist media. (4°C) for 4 months. Cuttings — Softwood or hardwood cut Aucuba Cuttings — Summer or fall cuttings root tings of C. stolonifera, C. alba root readily. (Gold Dust) easily. Use .3% IBA and bottom heat. Treat softwood cuttings with .2% IBA and Berberis Seed — Stratify 60 days at 40° F (4°C) or root under mist. Hardwood cuttings may (Barberry) fall plant. be taken in February or March, treated Cuttings — Root leafy cuttings under mist with .3% IBA and rooted on a bench with in mid-summer. Use .3% IBA and bottom bottom heat. heat. Grafting — C. florida is grafted onto seedlings. Betula Seed — Stratify 60 to 90 days at 40° F (Birch) (4°C) or fall plant. B. papery/era should be Cotinus Cuttings — To propagate pistillate plant frozen 4 to 6 weeks and then planted. (Smoketree) used as ornamentals, softwood cuttings are Graft — Cultivars of birch, primarily taken in early summer. Treat with .3% IBA B. pendula, are bud-grafted onto root- and root in greenhouse under mist. stocks of the same species. Cotoneaster This group of ornamentals is variable in Buxus Cuttings — Make cuttings in fall. Treat (Cotoneaster) propagation. Seed propagation is gener (Boxwood) with .3% IBA and use bottom heat. Soft ally unsatisfactory. C. horizontalis can be wood cuttings may also be rooted under grown from seed. Scarify in sulfuric acid mist. for 1 to \Vi hours and stratify at 40°F (4°C) for 4 months. Other species are best Calluna Cuttings — Summer in greenhouse (also propagated by cuttings. C. dammeri (Heather) in fall). Treat with .3% IBA or soak 24 easily as either softwood or hardwood hours in 50 ppm IBA. Root in peat-sand cuttings. C apiculatus and C. microphylla media. Bottom heat may help. can be rooted as softwood cuttings in Caragana Seed — Soak seeds and sow in field or August. Use .5% IBA. (Siberian Pea) stratify 60 to 90 days at 40° F (4°C). Seed — Complicated seed dormancy. Castanea Seed — Stratify immediately after harvest, (Hawthorn) Stratify warm 70°F (20°C) for 3 to 4 () 3 months at 40° F (4°C). months, then 40° F (4° C) 3 to 4 months, or Grafting — Cultivars of Chinese chestnut scarify with sulfuric acid 15 to 20 minutes are budded or grafted onto C. mollissima and then stratify at 40° F (4°C). . Grafting — Cultivars of C. laevigata (C. oxyacantha) are grafted onto seedlings. Catalpa Seed — Require no treatment. Store cool (Catalpa) and dry overwinter. Plant in rows in spring. Cytisus Cuttings — Can be rooted most any time (Scotch of the year, best in August to December. Seed — Place seed in hot water and let sit Ceanothus Broom) Treat with .3% IBA and give bottom heat. (Buckbrush, for 24 hours. Sow in beds. Stratification at Red Twig, 40° F (4°C) may be necessary for C. Daphne Cuttings — Leafy cuttings in June and Ceanothus) sanguinea. (Rock Daphne) July. Root in peat-sand media. Treat with .3% or .8% IBA. Use bottom heat and mist. Celtis Seed — Soak seeds 10 to 30 minutes in con (Hackberry) centrated sulfuric acid and plant into beds Deutzia Cuttings — Both softwood and hardwood (fall) or stratify at 40° F (4°C) for 3 to 4 (Deutzia) cuttings root easily. IBA treatment may be months for spring planting. helpful. Mist softwood cuttings in the greenhouse. Chaenomeles Cuttings — Although seed are easy to ger (Flowering minate, cultivars are maintained by cut Elaeagnus Seed — Stratify 3 to 4 months at 40° F ) tings. Early summer cuttings root readily (Russian , (4°C). Genus Genus (Common name) Propagation (Common name) Propagation Silverberry, Cuttings — Softwood or hardwood can be Larix Seed — Fall plant or stratify at 40° F (4° C) Autumn Olive) rooted. Softwood taken in early summer (Larch) for a month. and rooted under mist does best. Cuttings — Root young tips in early sum mer. Use .8% IBA and mist. Erica See Calluna. (Heath) Ligustrum Cuttings — Root softwood or hardwood Euonymus Cuttings — Root deciduous kinds from (Privet) cuttings. Hardwood cuttings taken in late (Burning Bush, softwood cuttings; evergreen kinds any winter will root in the greenhouse or can be Winter Creeper, time. Root easily. field rooted. Spindle ) Lonicera Cuttings — Most root easily from hard- Fagus Seed — Do not allow to dry. Stratify at (Honeysuckle) wood cuttings taken in late winter. Use a (Beech) 40° F (4°C) for 3 to 4 months. .1% or .3% IBA powder to speed rooting. Grafting — Most ornamental beech are Mahonia Seed — Do not dry the seeds, stratify im- bud grafted onto seedlings of F. sylvatica. (Oregon ) mediately at 40° F (4°C) overwinter, plant out in spring. Forsythia Cuttings — Root softwood cuttings June- (Forsythia) August. Treat with .3% IBA using mist and Cuttings — Use softwood cuttings treated bottom heat. Hardwood cuttings can be with a high concentration (20,000 ppm) rooted in February in the greenhouse or quick dip of IBA. Use mist. stored and field-rooted. Seed — Stratify 60 to 90 days at 40° F (, (4°C). Watch for germination. Fraxinus Seed — Stratify 3 months at 40° F (4°C). (Ash) F. excelsior requires a warm treatment of Crabapple) Grafting — All cultivars of apple and crab- 3 to 4 months before stratification. apple are grafted to a seedling or size- Grafting — Cultivars of F. pennsylvanica controlling . Budding in late and F. excelsior are grafted onto seedling summer is a useful method. Cleft or whip rootstocks. graft may be used in bench-grafting or field-grafting in spring. Genista See Cytisus. Mound layering — Size controlling root- (Broom) stocks are propagated by mound layering Ginkgo Cuttings — Although the Ginkgo can be or stool bed. (Ginkgo) propagated from seed, only the staminate culture — Virus-free rootstocks are trees are used in landscaping. Take soft propagated in tissue culture. wood cuttings in summer. Root in the Parthenocissus Cuttings — Root softwood cuttings in greenhouse under mist. (Virginia greenhouse in summer or hardwood cut Gleditsia Seeds — Scarify 1 to 2 hours in sulfuric creeper, tings in spring. (Honey locust) acid and then stratify at 40° F (4°C) for 3 Boston ivy) months. Pachistima Cuttings — Root softwod or hardwood Cuttings — Softwood cuttings in summer (Pachistima, cuttings. Use .3% IBA and peat-sand or hardwood cuttings taken in late winter Mountain lover)media. can be rooted. Philadelphus Cuttings — Root hardwood or softwood Hydrangea Cuttings — Softwood in early summer. (Mock , cuttings. A .1% or .39c IBA powder may (Hydrangea) Root under mist. Treat with .3% IBA. Syringa) help but cuttings root easily. Hardwood in late winter will usually root. Picea Seed — Most require 1 to 3 months of Hypericum Cuttings — Root softwood cuttings in (Spruce) stratification at 40° F (4°C). P. pungens (St. Johnswort) early summer in greenhouse. and P. engelmanii do not require stratifi Juniperus Seed — Germination is erratic. Seeds cation. (Junipers) usually germinate over a 2-year period. Cuttings — Difficult to root. Dwarf Al Treat seed with sulfuric acid for 30 min berta spruce and nest spruce are rooted in utes. Then stratify for 4 months at 40° F July and August. Use an acid media and (4°C) or fall-plant. bottom heat. Cuttings — Most of the spreadingjunipers Grafting — Selected clones of P. pungens can be propagated by cuttings. For and P. abies are grafted onto seedling root- J. chinensis, J. sabina, J. communis, use stocks (See Juniperus). .8% IBA powder or 4000 to 8000 ppm Pinus Seed — Most do not require stratification quick dip. For J. horizontalis, a .3% pow (Pines) but a 1to 3 month cold treatment may pro der will suffice. For J. scopulorum, J. duce more uniform germination. virginiana, use .8% IBA and wound cut Grafting — Ornamental cultivars are tings. Cuttings may be made from July to grafted ontl seedling rootstocks much the February. Root in sand or sand-peat same as Juniperus. media with bottom heat. Mist is not neces sary. Platycladus Cuttings — Ornamental cultivars are Grafting — Veneer or side graft to seed (Oriental propagated from cuttings taken from July lings of J. scopulorum, J. virginiana or arborvitae) to February. Use a .3% IBA powder and J. chinensis. Rootstocks should be brought bottom heat. into the greenhouse in December or Janu Populus Seed — Not practical except for aspen ary and forced into growth. After grafting, (Poplars, which is impossible to root. Collect seed sink pots into moist peat and cover bench Aspen) and plant immediately. Seed must never with glass or plastic. Occasional misting is dry out. Plant in sterile soil mix and give helpful. shade. Genus Genus (Common name) Propagation (Common name) Propagation

Populus (continued) Sorbus Seed — Stratify 3 to 4 months at 40° F (Mountain ash) (4°C). Cuttings Make cuttings in late winter Grafting — Ornamental cultivars are bud- and store at 35°F (1°C) until they can be grafted onto appropriate seedling root- planted in rows. Cuttings must be kept wet stocks. while rooting. Aspen can be propagated from root cut Spiraea Cuttings — Root softwood cuttings under tings gathered in late winter or early (Spiraea) mist in summer in a greenhouse, or hard spring. Place the rooted cuttings in flats of wood cuttings in late winter. Hardwood moist sphagnum or peat. New shoots will cuttings may be field-rooted. appear. These can then be rooted if de Symphori- Seed — Propagation from seed is difficult, sirable. carpos Stratify for 4 to 5 months at warm temper- Cuttings — Ornamental cultivars are (Snowberry) ature and 3 to 4 months at 40°F (4°C). Potentilla Cuttings — Hardwood, softwood and root (Cinquefoil) rooted from soft or hardwood cuttings. cuttings are easy to root. They are easy to root. Syringa Cuttings — Timing is of utmost impor- Prunus Seed — Seedlings are used as rootstocks. All require stratification at40°F (4°C) for (Lilac) tance. Take cuttingsjust before to just after (, Plum. flowering or when new shoots are 4 to 6 . 3 to 4 months. If possible, do not allow to dry out. Store moist and warm until strati inches long. Place under mist in a well- Cherry) drained media (sharp sand). Treat cuttings fication in cold. Cuttings — Some ornamental Prunus can with .8% IBA powder and spray bed with be rooted. Use softwood cuttings, mist, fungicide to avoid fungus attacks. Use bottom heat and 3% IBA powder. bottom heat. Grafting — Prunus cultivars are bud Grafting — Lilacs are usually grafted. A grafted in late summer onto appropriate bench graft is made to an ash or privet root. The rootstock acts as a nurse root rootstocks. until the scion roots. Pseudotsuga Seed Sow seed in fall or stratify at 40° F (Douglas fir) (4°C) for 2 months before planting. Taxus Cuttings — Take cuttings early winter. Grafting — Ornamental cultivars are (Yew) Root in sand with bottom heat. Use .8% grafted to seedling rootstocks (See IBA or higher. Leave on bench until well Juniperus). rooted. Thuja Cuttings — Softwood or hardwood cut- Pyrus Seed — Handle like Malus. Grafting — All cultivars of are grafted (Arborvitae) tings can be used. Treat cuttings with .4% (Pear) or .8% IBA. Wounding aids in rooting. onto appropriate rootstocks. Usually budding is done in late summer. Bottom heat is beneficial. Quercus Seed — Store cold and moist until ready to Tilia Seed — Scarify seed first in nitric acid for (Linden) 30 minutes, then in sulfuric acid for 15 (Oak) plant. Fall planting probably best. Protect seedbed from rodents. minutes. Then stratify at 40° F (4°C) for 4 months, or stratify warm for 4 to 5 . Rhus Seed —Do not allow seed to dry. Stratify months and then cold for 4 to 5 months. (Sumac) warm for 3 to 5 months, then cold (40° F, Grafting — Ornamental cultivars of linden 4°C) for 3 months. are bud-grafted to seedling rootstocks in Offshoots — The fern sumac, R. late summer. typhina 'dissecta' is propagated from root suckers. Tsuga Seed — Stratify 2 to 3 months at 40° F (Hemlock) (4°C). Ribes Cuttings — Ornamental currants are Cuttings — Some cultivars are propagated (Currants) propagated by softwood cuttings taken in by cuttings. Rooting is erratic. Take cut the summer. Use mist and .3% IBA. tings in late winter or mid-summer. Treat Rosa Grafting — Ornamental are grafted with .8% IBA and give bottom heat. () to clonal rootstocks. This is a very special Grafting — Cultivars may be grafted ized field of propagation and should be similarly to spruce (see Picea). attempted on a commercial scale only after Viburnum Seed — Stratify warm 4 to 5 months or considerable experience. (Various) until seed has produced roots, then stratify Salix Cuttings — The willows root very easily cool 40° F (4°C) for 3 months. (Willow) and can be treated like the poplars (see Cuttings — Take cuttings in mid- to late Populus). summer. Treat with .3% or .8% IBA. Use Grafting — Some weeping or prostrate bottom heat. Leave on the bench until forms of willows are budded onto stems to well rooted. give a specific ornamental effect. Vitis Cuttings — Root hardwood cuttings in Sambucus Seed — Stratify 3 to 4 months at 40° F (Grape, field. Take cuttings in late winter and store (Elderberry) (4°C). Germination is often erratic. Virginia cold until planting time. Vitis species may Cuttings — Softwood cuttings under mist Creeper, also be rooted in the greenhouse from root easily. Boston Ivy) summer cuttings.

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