So today I had an opportunity to take softwood and semi-ripe, tip nodal cuttings from material the Temperate House sent us, which was lucky, because most of the propagation in the nursery is done in autumn and winter, when plants are dormant.
As soon as we received them, one by one we dealt with the bags of material, taking it out on our potting benches and selecting the best stems to cut. All the material was labelled with the plant name and its accession number.
With a sharp blade, we mad a flat cut about 15 cm from the tip just under a suitable node (mostly to include some semi-ripe wood). Then pulled (or cut close to the stem, depending whether they came off nicely or peeled off some of the epidermis with them) all the leaves at the bottom. You usually leave only four at the top, so that photosynthesis does still take place and the cutting gets its food while putting out adventitious roots.
If you are restricted to material with any flowering tips on them (ideally you would get a non-flowering stem), the flower buds are best removed too, as they divert the plant energy from root formation (by releasing hormones).
- name of the commissioning entity in Kew,
- name of the propagator,
- name, accession number and conditions of the plant material,
- number and type of cuttings,
- treatment information (with rooting hormones, which have as active ingredients synthetic auxins, and often fungicide added to them, to protect the wound while it heals)
- composition of the rooting compost and location in the greenhouses.
As the cuttings are different sizes and numbers, depending on leaves and nodes's structure and the amount of available material, we soon found out that it is quicker to lay them down in advance to determine spacing (not much is needed, by the way: I used to keep more at home).
The bench is covered by a polythene tent to keep the moisture in and there is a heating pipe under the bed for bottom heat, which helps tissue to heal and roots to come out. The rule, as I studied it, is "warm bottoms and cold tops", so that the plant is encouraged to root before sending out more shoots, which (by requiring extra water and nutrients take-up) might put too much stress on the weak rooting system while it develops.
Day two at the nursery gone in a whiff.
Just a NOTE, for those of you interested in organic: hormone rooting powders/solutions are not allowed as they contain synthetic substances and fungicides. I hear that dipping cuttings in willow tea/water (water in which willow bark/young stems have been soaked) might help, as willow - an easily rooted plant - is rich in natural auxins. I have not used it but know someone that does, if you are interested in more.