Traditionally, side-veneer grafts have been used to propagate conifers, but they are now often carried out on any plant suitable for side-grafting. The join resulting from this method of grafting is slightly more upright than one from a side-wedge graft (see page 89).
Conifers, when cut, exude resin and, although this can be reduced by drying off the rootstocks before grafting, the resin will still adhere to a knife blade and so impair its efficiency and cutting edge. Therefore, keep the knife blade clean by wiping it regularly with some absorbent material soaked in an organic solvent such as ctc or acetone. It is important to wipe the solvent off the blade with a clean cloth otherwise it could pollute the tissues of any plant through which the knife blade subsequently cuts.
Rootstocks for side-veneer grafts are almost invariably pot-grown, as the fine, fibrous roots of the conifer are prone to drying out.
Graft conifers either in late winter/early spring or during late summer, although the latter period causes problems as the trees have to be kept alive over the winter and then need to be hardened off in spring.
In late winter/early spring, dry off the pot-grown conifer that will form the rootstock by watering less than usual. Because it is evergreen, this drying off should not be as drastic as for deciduous plants.
After three weeks, once the rootstock shows signs of growth, grafting is carried out.
Select a conifer that has suitable scion material and cut off a leader shoot of one season's growth. The length of the shoot, or scion, will very much depend on the vigour of growth, but it must include some mature brown-barked wood. Strip off the leaves from the bottom third of the scion. Make a in sloping cut down to the scion base, using a sharp knife. Then turn the scion over and make a very small wedge cut.
Trim any leaves off the bottom 6 in of the rootstock stem. About 2^-3 in above soil level, make a 1^in sloping cut downwards and inwards to give a shallow cut about ^in deep at the bottom. Then make a slightly downward and inward nick lower down the rootstock to join the first cut. Remove the sliver of wood from the rootstock. Place the rootstock and scion together. If their sizes match they will be easier to manipulate. If the scion is narrower than the rootstock, set to one side to match up the cambial layers. The interlocking bases of the two grafted parts will provide some rigidity, but they should also be tied together firmly.
It is possible to use a rubberized strip as a tie, but clear polythene tape is just as effective and has the added advantage of preventing water loss from around the cuts.
4 Make a 1j in sloping cut down to the scion base. Make a very small wedge cut on the other side.
5 Trim any leaves off the bottom 6 in of the rootstock. Make a in shallow cut at the base.
6 Make a slightly downward and inward nick lower down the rootstock to join the first cut.
Label the grafted rootstock and keep it warm and humid to encourage the plant to grow and the grafted parts to join up. A closed case with or without heat from below is a suitable environment.
Water the pot sparingly, keeping the plant on the dry side until callusing occurs.
Conifers, if grown close together in pots under warm, humid conditions, are subject to various leaf diseases and rots, and to red spider mite infestations, so spray regularly with fungicides and pesticides.
Take the grafted rootstock out of the closed case and harden off on the greenhouse bench, once the parts have united. This should be within six to ten weeks. Remove the polythene tape and reduce the top of the rootstock by one-third immediately. After a fortnight, remove a further third. After midsummer, head back any remaining rootstock.
1 Select a pot-grown conifer that will be suitable as rootstock. Dry it off in late winter.
2 Select a conifer that has good scion material. Cut off a strong shoot that has some mature wood at its base.
3 Strip off the leaves from the bottom third of the scion.
7 Remove the sliver of wood. Place the rootstock and scion together and tie with polythene tape. Label.
8 Place in a warm, humid area while the two parts unite. Spray regularly with fungicides and pesticides.
9 Harden off once the parts have united. Remove the tape and gradually head back the rootstock.
Was this article helpful?
You Might Just End Up Spending More Time In Planning Your Greenhouse Than Your Home Don’t Blame Us If Your Wife Gets Mad. Don't Be A Conventional Greenhouse Dreamer! Come Out Of The Mould, Build Your Own And Let Your Greenhouse Give A Better Yield Than Any Other In Town! Discover How You Can Start Your Own Greenhouse With Healthier Plants… Anytime Of The Year!