Amateur Gardening 21-Jul-2018

THIS week I was going to hard prune one of our two overenthusiastic Clematis montana right back to the ground. It is a rampageous plant and often smothers windows and patio doors, so a hefty trim seemed a good way to solve this problem for the rest of the summer. I gave the other clematis the same treatment three years ago after flowering and it came back with gusto. However, this year’s plan has been put on hold due to the extremely hot and dry weather. Hard pruning can be traumatic for a plant, so I decided instead to just give it a thorough trim, but leave the canopy and stems attached until conditions become cooler and wetter. Clematis are one of our most popular, exotic-looking plants, and with good reason. The many…

1 Group 1: Early-flowering varieties such as C. armandii, C. cirrhosa ‘Freckles’ (pictured) and C. Montana. Simply tidy up new growth after flowering. 2 Group 2: Large-flowered varieties such as ‘Belle of Woking’ (pictured) blooming May-June. Prune early spring, keeping a framework of old wood. 3 Group 3: Flowering late summer, cut back old stems to the lowest pair of healthy buds in February or March. Ideal for ‘Gypsy Queen’ AGM (pictured). 4 Groups 2 & 3 combined: Cut some branches to the main framework and the rest back to the base. Varieties include ‘Abundance’ (pictured). 5 Herbaceous clematis: This group includes C. heracleifolia (pictured) and should be pruned back to ground level in late autumn or early spring. 6 Unknown group: If they flower before June, like C. montana (pictured) just trim back to…

It is extremely disheartening to see a previously healthy clematis shrivel and blacken almost overnight. There are usually two main reasons for this. Environmental problems are a key culprit. Clematis like their roots buried deep in moist, fertile soil that is in the shade. Their top growth should be in sheltered sun or partial shade. If planted against a wall or next to other shrubs, make sure the roots aren’t in a rain shadow. If possible, plant 2ft (60cm) away from a wall. Another problem is the fungal disease clematis wilt, which is more likely to attack large-flowered varieties than those that have smaller blooms. Leaves and stems shrivel and blacken, but don’t die. Cut back all the stems to healthy growth and wait for new stems to shoot back up from ground level. Disinfect…

GOOD warm weather brings gardens back to life and the same applies to houseplants, which should be in full growth now. Some can go outside (see Anne Swithinbank’s Masterclass on page 35), but whether they are in or out they require the same sort of care. Houseplants need regular watering and should also be fed with a liquid houseplant food (or specialist feed where applicable) once a fortnight. When you do so, check them over for pests, especially more tender varieties of plants that are spending summer in the warm, still security of the house. Scale insects, aphids, mealybugs and glasshouse red spider mite are common summer threats and should be controlled as soon as you see them. Scale insects have a hard shell that makes them almost impervious to houseplant pesticides. Before…

Summer is the perfect time to propagate African violets (Saintpaulia) and streptocarpus via leaf cuttings as they will soon take and form new plantlets in the warmer weather. With the Saintpaulia, simply remove a healthy, mature leaf from the parent plant and insert its stem into a 3in (7cm) pot of dampened seed compost and perlite. Seal the leaf in a plastic bag, which can be removed once new leaflets form at the base in a few weeks’ time. The large leaves of streptocarpus can be split lengthways, their hard spine removed and the cut edges inserted in a tray of damp seed compost and perlite, as before. Treat the same as the African violet leaves, and leaflets should start to form in a few weeks. Plantlets of both varieties can be potted up once…

1 Deadhead flowering plants regularly to encourage more blooms, and remove wilting and damaged material that might become diseased. 2 To keep your plants looking good, cut off dead leaves using clean scissors or snippers. 3 Regular feeding and watering is essential to promote healthy growth. Wilting will knock back plants and make them weaker. 4 Honeydew excreted by sap-sucking pests attracts sooty mould that can reduce photosynthesis. Wipe leaves clean with a soft, damp cloth and then spray with houseplant pesticide.…