To do in May
Time to think of winter protection where heavy frosts are experienced. In the summer rainfall areas, as there is now no prospect of rain for the next eight months, start watering shrubs, roses, fruit trees and vines. Many shrubs and trees are showing there autumn colours. The stately Liquidambars are rich crimson with touches of scarlet, the Tulip tree and the Maidenhair tree are pure gold this month, and in some districts the apricot trees and Lombardy poplars are now a golden yellow. But perhaps the most spectacular tree of all in autumn is the Wax tree with its almost indescribable display of colours.
HARDY SUMMER FLOWERING ANNUALS
Water once a week during dry weather and feed once a month with liquid fertiliser to maintain steady growth. Water in the morning in areas that experience frost, so that the foliage has time to dry before nightfall.
WINTER FLOWERING ANNUALS
- Feed twice a month with liquid fertiliser.
- Remove faded flowers regularly, especially from Iceland poppies, pansies and violas.
- Water during dry weather, doing this in the morning in areas that experience frost.
- Larkspur and stocks: If the lower leaves turn yellow this is a sign of nitrogen deficiency. To remedy this give the plants a dressing LAN. Dissolve 60g of LAN in 5 litres of water and apply to a square metre. Do this once a month for two or three months, or until the plants are healthy and green again. Water before and after application.
- Sweet peas: Tie the plants to their stakes or trellis as they grow, and remove tendrils and side shoots so that nutrients are not wasted on unnecessary growth. Increase the water supply as the plants grow. Water at least once a week in the summer rainfall areas.
- Tidy up plants as they die down, removing old flower stems and dead leaves.
- Mulch with compost and water once a month in the summer rainfall areas.
- Where plants were attacked by mildew during summer, spray thoroughly with fungicide.
- Anemone japonica, Michaelmas daisy and physostegia can still be lifted this month if they are overcrowded.
SUMMER FLOWERING BULBS
- Cannas: Once the foliage has died back, cut the stems down to ground level. In areas that experience frost cover the plants with a deep mulch of coarse compost to protect the rhizomes.
- Dahlias: As soon as the foliage has died down, cut the stems down to 15 to 20cm. Tie all labels securely to the stems. If the tubers are to be left in the ground in the summer rainfall areas cover them with a deep mulch of coarse compost. If the tubers are to lifted and stored for winter, first cut off the tails by pushing a sharp spade down vertically into the ground about 15cm from the stems, then lift carefully. The tubers can be placed in a trench in the garden and covered with soil. If they are to be stored in boxes wash the soil off, place the tubers in the boxes, cover with peat or sand and store them in the garden shed. Water lightly from time to time during winter. Do not store the tubers without any covering as they will shrivel and be of no use next season.
- Liliums: When the foliage has died down, cut the stems off and cover the plants with compost. Mark their positions with a ring of small stakes.
- Summer rainfall areas: Water agapanthus, day lilies and liliums at least once a month.
WINTER FLOWERING BULBS
- As the bulbs come up water more frequently, about once a week in the summer rainfall areas.
- Water narcissi, daffodils and other exotic bulbs, which have not yet come up, about twice a month.
- Warm frost-free areas: These bulbs can still be planted:
- Allium neapolitanum
- Anemone coronaria
- Aristea thyriflora (tall aristea)
- Bulbinella latifolia (cat's tail)
- Dipidax triquetra (star of the marsh)
- Iris (Dutch iris)
- Hyacinthus orientalis (hyacinth)
- Ipheion uniflorum (star of Bethlehem)
- Ixia (wand flower)
- Leucojum (snowflake)
- Lycoris radiata (spider lily)
- Muscari botryoides (grape hyacinth)
- Ornithogalum thyrsoides (chincherinchee)
- Ranunculus asiaticus (ranunculus)
- Schizostylis coccinea (river lily)
- Sparaxis (harlequin flower)
- Feed calceolarias, cinerarias, cyclamen, daffodils, hyacinths, jonquils, narcissi, poinsettias and primulas every two weeks with a liquid fertiliser.
- Water about every three days or when the soil feels dry.
- Discontinue feeding other pot plants if this has not already been done.
- Water less frequently, but never let the plants, especially ferns, orchids and philodendrons, become completely dry.
- Once the foliage of amaryllis , caladiums, achimes and tuberous rooted begonias has died down, reduce watering to a light sprinkling from time to time to prevent the soil becoming bone dry.
Winter rainfall and warm frost-free areas: Mow if necessary.
Summer rainfall areas: Water the grass about once a month.
- Take hardwood cuttings: Hardwood cuttings that were not taken last month can still be taken now.
- These must be of fully matured wood, which developed in the past spring or early summer.
- The cutting should be about 20 cm long after the immature tips have been removed.
- Cut just below a node or leaf joint.
- Remove the leaves from the bottom two thirds of each cutting.
- Root the cuttings in the open ground.
- Make a v-shaped trench in the garden about 15 cm deep and put a thin layer of sand at the bottom.
- Dip the end of each cutting into a rooting hormone and then position the cutting in the trench.
- Fill the trench with soil, firm it well and then water.
- In the summer rainfall areas keep the soil damp, but not saturated, during winter and early spring until the summer rains starts.
- The cutting should be ready to plant in their permanent position in the garden in the winter or early spring of next year.
- Protecting from frost:
- In areas where frost is experienced it is necessary to provide winter protection for tender shrubs such as proteas, beloperones, cupheas, daturas, fuchsias, hibiscus, poinsettias, etc.
- Small shrubs can be covered with large cardboard boxes.
- To protect large shrubs place four stakes round each shrub and drape hessian over these every night all through winter.
- Remove the boxes and hessian covers every morning.
- Protect the roots by covering the ground around the plant with a deep
mulch of compost or bark.
- Summer rainfall areas: Water azaleas, camellias and all shrubs from
the winter rainfall areas once a week.
- Water vegetables regularly during dry weather.
- Feed with Multifeed P every two weeks to improve the flavour of the vegetables.
- In warm frost-free areas spray tomatoes once a week against blight.
- Asparagus: Prepare trenches. Before preparing the trench clear the ground of perennial weeds such as couch grass. Dig trenches any convenient length but remember that the crowns must be spaced 45cm apart. Make the trench 45cm wide and 25 to 30cm deep. Break up the ground at the bottom of the trench then return the soil, mixing it well with plenty old sifted compost and/or old, well-rotted manure and a dressing of 2.3.2. at the rate of 120g per metre of trench.
- These vegetables can be sown in the various regions this month:
- Gauteng and OFS Highveld
- Lowveld and warm frost free areas
- OFS and Northern Cape
- Kwa Natal Midlands
Eastern Cape and Karoo Broad bean Garlic Onion Radish
- Western Cape: Winter rainfall areas Beetroot Broad been Cabbage
Carrot Dwarf spinach Endive Garlic Horseradish Kohlrabi Leek Lettuce Onion
Parsley Parsnip Peas Radish Swede turnip Turnip