Hard Wood Cuttings
I wrote previously about taking root cuttings. On this occasion I will focus on another winter propagation method, hardwood cuttings. This is possibly the easiest form of propagation, it requires no specialist equipment such as a propagation unit or trying to make a home made version. What it does require is patience. It is possible that way back a cave man noticed that the willow branches that he had stuck into the ground had rooted and made new plants. Willow (Salix) naturally has high concentrations of hormones needed for rooting cuttings. Other species generally need some help with hormone rooting powder.
The success rate of hardwood cuttings may not be as high as other methods such as softwood cuttings. But given that there is less effort involved it is still very much worth pursuing. Particularly when you factor in the rising prices of just about everything. Depending on what you are buying and who from, you can expect to pay about £15 upwards for a specimen in a 2-3lt pot. In the case of David Austin Roses, a rose will cost between £21.50-£30 depending if it is bare-root or potted. However it must be noted that you can only propagate David Austin Roses or any other plant with PBR (Plant Breeders Rights) for your own use and not to sell on. Unless you are prepared to pay the royalties.
Hard wood cuttings are generally a lot bigger than softwood or semi-ripe cuttings, since they take longer to root and need the extra food reserves to get them through the winter. They are typically around 20cm (8in) long, about the length of a pair of secateurs. Firstly, cut each shoot at the base of the current season’s growth. Next trim of the tip of each shoot if it has not ripened. Then cut the shoots into 20cm sections. Make a horizontal cut below a node at the base of each cutting and a sloping cut sloping away from a bud at the top. This way you will know which end is which and maintain the correct orientation.
Prepare a slit trench in free draining soil by pushing a spade into the soil about 15cm (6in) down and press the blade forwards to open out the trench. Dip the base of each cutting in hormone rooting powder. Insert the cuttings about 5cm (2in) apart so that about a quarter of each cutting is visible. Rows of cutting should be about 30cm (12in) apart. Backfill the trench and firm the soil around the cuttings. Label, and water if the soil is dry. For smaller quantities insert the cuttings, as above into 15cm (6in) pots of loam-based cuttings compost, about four per pot. Do not forget to label each batch.
Roses are perfectly fine grown on their own roots. They are mainly budded commercially onto a rootstock to maximise the use of propagation material and faster results. We are currently taking cuttings from Rosa odorata ‘Mutabilis’. There are various shrubs that can be propagated in this manner including Forsythia, Deutzia, and Philadelphus. If the Philadelphus from the national collection have put on good growth, we may propagate them using this technique. Willow and Cornus (Dogwoods) are also often propagated by this method. Some evergreens can be propagated by hard wood cuttings such as cherry laurel (Prunus Laurocerasus) and Elaeagnus. These are treated differently to deciduous subjects, mainly that they will still have leaves. The leaves from the bottom half of the cutting are stripped off. Bottom heat will speed up rooting. It is also beneficial to place evergreen hardwood cuttings in a plastic film tent to keep the cuttings humid.
Hardwood cutting offer a straightforward means of producing extra plants. It does require patience, however. Cuttings should be ready to be dug up and transplanted to their permanent home in the autumn. Hopefully we will have some new plants to replace some of the old specimens and fill in some gaps in the next planting season.
William Stanger. M.A. of Four Winds Horticulture is a local Garden Consultant. He is advising Whatton House on the garden’s regeneration. He has worked at various gardens in the U.K and New Zealand.