“propagation” and “right plant, right place”
The Gardeners’ Club enjoyed another very practical Zoom talk on 4 November by Chris Bird, a lecturer from Sparsholt College, on propagation methods for growing plants.
He started by explaining that all seed packets are marked with a ‘sow by date’ and good prices can often be found in garden centres just before Christmas. If you are buying vegetable seeds be aware that those labelled F1 hybrids are all genetically identical so will reach maturity at the same time. You can also collect your own seed pods before they split and store them in envelopes or small jars.
Large seeds are easy to handle and can be sown in seed trays or individually in pots. Some varieties of sweet pea seeds are hard coated and can be placed in a bowl of boiling water and left for 24 hours before sowing. Alternatively use a sharp knife to nick the outer shell or rub it gently with sandpaper on the opposite side to the seed’s black ‘eye’ or scar, which will improve the germination rate from 40% to nearer 90%.
Medium sized seeds can either be sown in a seed tray or in Jiffy 7 pellets which contain a well-balanced starter fertiliser and avoid root disturbance, resulting in better plant survival. Very fine seed should be mixed 50:50 with dry silver sand so that you can see where you have sown it. Don’t forget to label each tray! Pot up the seedlings as soon as you can handle them by a leaf, never by the delicate stem. A basic rule of thumb is that they are ready to plant out in the garden when there are ‘six true leaves’. The soil temperature should not be less than 10 - 12°C, which is when worm casts start to appear.
Plants can be propagated using softwood cuttings. Choose a shoot with a strong healthy looking tip and cut it just above a node (leaf joint) so that it is at least 10-13 cm long. Trim the base of the cutting to just below the first node, where the hormones are strongest, and reduce the top so that it is about 8-10 cm long. Finally remove the leaves from the bottom third of the cutting, by pulling them gently downwards, before placing it in the compost. It is from these small wounds that the roots will emerge.
Hardwood cuttings can also be taken in late autumn and early winter. They should be about the thickness of a pencil and removed in the same way as a softwood cutting. Trim the base to just below the first node and reduce the length to about 15 cm by cutting off the top at an angle, so that you know which way up to plant it. Space them around the edge of a pot or bury them in a trench with only a third above the soil and leave for a year, making sure that they never dry out. An instructive book for beginners is ‘Grow your own Garden’ by Carol Klein.
Chris then moved on to the question of choosing the correct conditions for a plant to thrive and suggested that we should not dismiss traditional plants, which are easy to grow and have a wide flowering season. Examples of plants tolerant to full sun or partial shade are: Acanthus spinosus which is good in clay soil and wet conditions; Alchemilla mollis or lady’s mantle – Prince Charles’ favourite – with sprays of tiny yellow flowers and tolerant of any type of soil, as long as there is some moisture; Bergenia cordifolia, an incredibly hardy evergreen perennial with erect clusters of deep-pink flowers in early Spring, and best grown in moist but well drained soil; Heucheras with low, flattened mounds of foliage, which come in many different leaf colours and are good at filling in gaps between taller plants; and Berberis darwinii, a hardy medium-sized evergreen shrub with dark glossy evergreen leaves and drooping racemes of orange flowers in Spring.