Topical Tips for August
Now is a good time to create new plants.
PROPAGATION: SEED SOWING
August is a good time to collect seeds from early Spring flowering plants. Save up your old envelopes and make a point of collecting the seeds as soon as the pods are ripe or almost ripe, on a dry day e.g. hellebore, erythronium, fritillaria, camassia, trillium and members of the cow parsley family. Write the name of the plant on the envelope and the collection date. Depending on the number of seeds and the number of plants you would like to grow on, use small pots or modular tray inserts (I use a 40 section insert tray inside a standard seed tray). The compost I use is my standard peat free Melcourt Potting Compost (made out of well composted bark), without the addition of fertiliser. Sow the seed thinly and evenly. I then put a thin layer of potting bark on the surface to deter weeds, liverwort and slugs. Having watered the tray/pots without displacing the seed, they are then placed in a shady position outside. This method avoids the extremes of temperature to be found in a greenhouse and imitates natural growing conditions. The seed hopefully then germinates like ‘cress’ next Spring if not earlier. Once the roots have filled the modules pot up each section. Do not separate the seedlings.
IRIS GERMANICA (BEARDED IRIS)
Perhaps the most commonly thought of member of the Iris family is the bearded iris with its huge impressive flowers, liking full sun and alkaline soil. This iris is the one to propagate now if the rhizomes are congested. Dig the whole plant up, discard the very oldest rhizomes and replant the younger ones at the surface with the root aligned to face the sun. Trim the leaves back to 15cm to stop any wind rock. Before replanting improve the soil with a general fertiliser and look forward to a renewed vigorous show of flowers next year. The iris family is vast. Some like growing in shallow water e.g. Iris pseudacorus, some like shady sites e.g. Iris foetidissima, some like neutral to acid soil conditions in full sun e.g. Iris ensata (Japanese Iris) whilst others like sun or semi-shade and any reasonably fertile soil e.g. Iris sibirica.
PENSTEMON, SALVIA AND HYDRANGEA
Cuttings can be taken now. I like to take these first thing in the morning and deal with them straight away. Take a semi-ripe stem and cut below a pair of leaves (node). Measure approx. 10cm along the stem and cut above a node (pair of leaves). Several cuttings can be made from one stem. Discard the tip of the stem. Remove any flower buds. Make a mix of 50:50 coarse grit and vermiculite, put into a small plastic pot and insert your cuttings around the edge (where there is more air). Put into a propagator or plastic bag and check after 4 or 6 weeks to see if roots have appeared at the bottom of the pot. Pot the cuttings up individually using compost which does not contain too much fertiliser and put the young plants into a cold frame to overwinter or bring into the frost free greenhouse late October.
OTHER AUGUST JOBS
- Regularly pick runner beans to keep them cropping.
- Cut back extension growths on rambler roses if they are getting out of hand.