Organic Gardening Tips and Methods Ornamental Trees (Part 10, Section 1) Propagation; Trees may be propagated from; cuttings, seed, layering, or grafting. Taking cuttings is probably the most common method of propagation as it is fairly simple and provides new plants relatively quickly, while raising trees from seed or layering is easy but very slow. Grafting is rarely used by amateur gardeners because it requires considerable expertise to grow new plants successfully this way. Tree species may be propagated from seed but hybrids and cultivars rarely come true to type, vegetative methods of propagation, such as taking cuttings, layering, and grafting, may be used for hybrids and cultivars as well as species, however, some care in the selection of plant material is required in order to be successful. Hardwood Cuttings; Many deciduous trees may be propagated from hardwood or dormant cuttings. In early autumn prepare the ground for the cuttings while it is still warm, cuttings can be inserted either outdoors in open-ground or, for trees that do not root very easily, in the more stable environment of a cold-frame (or a “large-enough” greenhouse/glasshouse). Cuttings of trees that root easily such as willows (Salix) may be inserted directly into a trench while those that are more difficult to root such as; Metasequoia should be inserted into a sand-bed, and then transplanted into a trench early the next spring. In either case, make the trench narrow and with one side vertical so that the cuttings are held upright while they are rooting. The depth of the trench will depend on the type of plant required, for multi-stemmed trees it should be 2.5cm (1in) shallower than the length of the cuttings, for single-stemmed trees it should be the same depth as the cuttings so that the top-bud is barely covered and the lack of light inhibits the growth of all other buds, for best results; dig the trench in a friable, well-drained soil, in heavy clay soil: add some coarse grit or sharp/coarse sand to the base, if preparing a few trenches, space them 30-38cm (12-15in) apart in open-ground, or about 10cm (4in) apart in a cold-frame. Preparing and Inserting the Cuttings; Select the cuttings just after leaf-fall, choose strong, vigorous shoots of the current season’s growth and remove them by cutting just above a bud or a pair of buds at the junction between the current and previous seasons growth, trim down the cuttings and dip the basal cuts in hormone rooting powder to encourage them to root, place the cuttings against the vertical side of the trench at the correct depth and backfill with soil, then firm in gently and water well. For species that doo not root easily, tie the cuttings into bundles of no more than ten and then plunge them in a sand-bed in a cold frame for the winter where they should root before being transplanted. Aftercare; Label the cuttings and leave them until the following autumn, during winter, the ground may be lifted by frost: re-firm the soil around the cuttings, if this occurs by autumn, the cuttings should be well-rooted and may then be transplanted individually into open ground or into containers as required, if they have been kept in a cold-frame, harden them off in the first spring, then transplant outside, the following spring, pot them up or move them to their final position in open ground. Semi-Ripe Cuttings; Many conifers as well as certain broadleaved evergreens such as Magnolia grandiflora and Prunus lusitanica may be propagated readily from semi-ripe cuttings, these cuttings are taken in late summer or autumn from stems that have virtually ripened that is when they have thickened and become harder. Selecting the Cuttings; In a closed case at 21 degrees C (70 degrees F) or in a cold-frame, prepare a suitable rooting medium for the cuttings, for example: this might consist of equal parts of grit and peat-substitute or peat, using a sharp knife take heel cuttings from healthy side-shoots, including a sliver of hardened wood from the main stem, alternatively take 10-15cm (4-6in) long cuttings from leaders or side-shoots and trim immediately below a node. For cuttings from conifers, choose leaders or side-shoots that are characteristic of the parent plant, as conifer shoots vary considerably in their growth patterns, it is particularly important to select cutting from material carefully from slow-growing (dwarf) conifers; some plants may produce reverted or uncharacteristic shoots, but only use shoots that typify what you want to propagate. Preparing and Inserting the Cuttings; With both types of cuttings, cut off the lower leaves with a sharp knife and reduce the remaining leaves by a third or a half to minimize the loss of moisture, if the cutting tips are soft, pinch them out to encourage the cuttings to root, use the tip of the knife to make two shallow, vertical wounds about 2.5cm (1in) long on opposite sides of each cutting down to the base, alternatively, make a longer wound along the side of each cutting with a knife and remove a sliver of bark as well, in either case, dip the basal cut, including the wound in hormone rooting powder, insert the bottom third of each cutting in the rooting medium, taking care to leave enough space between the cuttings so that they do not overlap, this allows air to circulate freely around them, then firm the compost, water in thoroughly with a solution containing fungicide and label them (the cuttings). Aftercare; Check the cuttings periodically watering them only to keep them from drying out; remove any fallen leaves as soon as they appear since these may spread disease to the cuttings. In frosty conditions, cold-frames should be insulated with hessian or a similar covering, if the cuttings are being kept in a closed case with basal heat they should root by early spring. Cuttings in a cold-frame are usually left until the following autumn, although it is preferable to leave them in a frame for a second winter and pot them up the following spring. During the summer, mist spray the cuttings frequently to stop them from drying out, if the cuttings are in strong, direct sunlight, they risk being scorched and it may be necessary to shade them: apply a greenhouse/glasshouse shading paint or place shading material over the frame, once the cuttings root, lift them out carefully with a hand-fork and transplant them into individual pots, then harden them off before potting them on further or planting them out in open ground. Rooted cuttings may be hardened off while still in the frame by raising the frame cover for short then longer periods of time, once they are sufficiently well rooted, pot them up or transplant them outside. If there may be a delay before potting up, give a liquid-feed to the rooted cuttings in the interim. Softwood Cuttings; This method of propagation is suitable for birch (Betula), Metasequoia, some ornamental cherries (Prunus), and a few other tree species, although it is more commonly used for shrubs, softwood cuttings are taken in spring from the fast-growing tips of new shoots and usually root very easily, they wilt rapidly, however, so it is vital to prepare and insert them as quickly as possible after removing them from the parent plant. Preparing and Inserting the Cuttings; In spring, before taking the cuttings, prepare containers by filling them with a appropriate compost and then firming to just below the rim, take the cuttings by removing the new growth from the stem-tips, cutting just above a bud or leaf-joint with a sharp knife or secateurs, to reduce any moisture loss, immerse the cuttings in water straight away or place them in an opaque, plastic bag and seal it, even a small loss of water/moisture will hinder the development of new roots, prepare the cuttings by trimming them with a sharp knife to about 6cm (2.5in), cutting just below a leaf-joint, remove the lower leaves, the base of each cutting can be dipped in hormone rooting powder to encourage rooting, insert the cuttings into the prepared pots/containers of compost, label them and water them with a dilute solution of fungicide. To encourage rapid rooting, place the pots/containers in a mist unit or closed case at 21-24 degrees C (70-75 degrees F), preferably with basal heat, and water with a fungicide once a week to protect against rotting and disease, once they are rooted, the cuttings may be hardened off gradually before they are transplanted carefully into individual pots or out into open ground. Trees to be Propagated from Cuttings: Hardwood; • Cordyline *, • Ficus *, • Metasequoia glyptostroboides, • Morus, • Platanus, • Populus, • Salix Semi-ripe; • Austrocedrus ^, • Calocedrus ^, • Chamaecyparis ^, • Cinnamomum *^, • x Cupressocyparis ^, • Cupressus ^, • Drimys winteri, • Eucryphia, • Grevillea *, • Hoheria, • Ilex, • Juniperus ^, • Ligustrum lucidum, • Magnolia grandiflora ^, • Metrosideros excels *, • M, robusta *, • M, umbellata *, • Michelia *^, • Nothofagus dombeyi, • Podocarpus (some) *^, • Prunus lusitanica, • Quercus ilex ^, • Q, myrsinifolia ^, • Q, semecarpifolia ^, • Schefflera, • Taxus, • Thuja ^, • Thujopsis ^, • Trachodendron aralioides ^, • Tsuga ^, • Weinmannia, Softwood; • Acer cappadocicum, • Betula, • Catalpa, • Celtis occidentalis, • Cotinus coggygria, • Eucryphia lucida, • Ginko biloba, • Halesia, • Koelreuteria paniculata, • Lagerstroemia (some) *, • Liquidambar styracifolia, • Metasequoia glyptostroboides, • Pistacia, • Prunus, • Ulmus, Note; Symbol * = not hardy Symbol ^ = take cutting with a heel Note; All information given coincides with the guidelines of; The Royal Horticultural Society (RHS).
Posted on: Mon, 17 Mar 2014 13:40:03 +0000
Trending Topics
Recently Viewed Topics
© 2015