GARDENING TIPS FOR MAY February 21, 2008
Autumn is the month to collect the leaves fallen from deciduous trees to make leaf mould. It is best to leave the leaves that have fallen under established shrubs and trees where they are, as a natural mulch, but those that have fallen among smaller plants and on grass and paving should be raked up and put in black bags. If they are dry, dampen well, sprinkle on a handful each of lime, crumbled, well rotted manure, and bone meal. Tie up the bags and keep in an out-of-the-way place until they decompose. Although this is a long process – it could take 12 months – the resultant leaf mould is excellent to enrich your soil.
Keep your compost heap covered to prevent them from getting too wet, which will inhibit the action of the soil microbes, which break down the plant matter. Continue to turn the heap regularly, at 6 to 8 weekly intervals. Well rotted manure – cow or chicken added to the compost heap will speed up the breaking down process.
The weather and therefore the soil should have cooled down by now, so make sure all your spring flowering bulbs are planted before its too late! (See April Tips)
Finish planting out winter and spring flowering annuals. Primulas, foxgloves, cinerarias, pansies and violas are suitable for shady areas, whilst other annuals, such as Virginian stocks, calendulas, Bellis perennis, snapdragons and Iceland poppies do well in sunny spots. Remember to feed regularly with a food such as Nitrosol, Organiksol, Seagro, or Rapid Raiser. Alternate your food for best results. Watch out for snails, slugs and other nasties that will decimate your young plants in a very short time!
Even though the weather has cooled down, it is a good idea to keep all your beds mulched. This helps the soil from becoming compacted by heavy rainfalls (hopefully!) and also protects the plants from the cold. Adjust your automatic irrigation systems to take into account the increased rainfall. Remember that in some areas, such as under large, leafy trees and the eaves of the house or the lee of walls and hedges, rain may not be reaching the plants, which will probably need watering.
Plectranthus plants have made a wonderful show during the past month. Once they have finished flowering, cut the plants back hard to encourage new, strong growth for next season. Plectranthus plants are easy to grow from slips, so take this opportunity to take cuttings and grow more plants to fill your garden next season. The cuttings should be about 5cm in length and cut just below a node. Remove all the leaves except the top pair or two and place the cuttings in a very well drained medium, such as washed river sand, to root, which should take about 14 days. Keep the cuttings damp, but not too wet, and in a place that has adequate light, but not direct sunlight. Remember to label. After about a month, rooted cuttings can be planted out into suitable pots to grow on until large enough for planting in the garden.
Cut off the flower stalks of Japanese Anemones once they have finished flowering and tidy up clumps of perennials such as Michaelmas daisies, golden rod and obedience plants, and apply a layer of compost. These perennials can be moved this month if needs be.
Fertilise winter flowering shrubs now with Rapid Raiser and replenish the mulch. But note, this does not apply to Camellias and Azaleas. These plants, if fed at this time of the year, will make too much leaf growth, which will hide the flowers. These plants will, however, benefit from an application of acid compost or leaf mould made from oak leaves or pine needles.
Roses should be dormant by now, so feeding and deadheading is unnecessary. Collect any fallen diseased leaves and burn to prevent the spread of the disease. You could water or spray the plants with condi’s crystals - 1 teaspoon in 5l of water - to harden them in time for the late winter pruning.
Cyclamen plants will have started their new growth. Keep the plants in a cool place in bright filtered light, but never in direct sun. (Cyclamen like the cold, so you could stand your plants outside at night.) When watering don’t pour the water directly onto the tuber, which could cause it to rot. Rather water from below, but never leave the pot standing in water for more than about 10 minutes. Don’t water the plants too often – the plant will come to no harm if allowed to dry out between waterings. Feed with a suitable pot plant food every 2 to 3 weeks.
If you are planning to plant trees and shrubs for their autumn colours, now is a good time to visit the nursery to see which species and cultivars produce the most attractive and colourful foliage.
In the Cape, May is the month to sow sweet pea seeds. Dig a trench about 75cm deep, mix some compost and well-rotted manure with the soil and replace. Soak the sweet pea seeds in warm water overnight to soften the hard outer coat to assist in germination, and plant the seeds in holes about 5cm deep. Remember, sweet peas need full sun and are greedy feeders, needing plenty of water and a food high in potash every 2 weeks. The soil MUST be well drained. Why not try the bush varieties in a container for a change.
Winter is a good time to grow spinach, onions, carrots, leeks, peas, broad beans and turnips, as well as most of the brassicas. Keep your vegetables mulched and feed with a suitable food – Bounce Back, Rapid Raiser, Nitrosol, Organiksol or Seagro etc. Nip out the growing tips of broad beans to encourage the setting of pods. Shore up your cabbages, cauliflower and broccoli to stop them being blown over by north-west gales. Keep a lookout for slugs and snails, as well as the caterpillars of the Cabbage White butterfly on the brassicas.
Check your gutters and stormwater gullies and clean out leaves and any other debris to prevent flooding when we get the expected heavy winter rains.
