Gardening in May is like putting a baby to bed… You clean it up by removing all refuse, feed it to make it strong for cold months ahead, play around a while by planting something new, kiss it good night and cover it warmly with an organic blanket, before putting out the light.
The leaves of heavenly bamboos (Nandina domestica and N. ‘Pygmaea’) will start turning rusty red. Camellia sasanqua hybrids, which can tolerate more sun than the japonicas, will be in flower. In the indigenous patch you will have much eye candy with wild dagga, ribbon bush, Cape honeysuckle and the very elegant Strelitzia reginae (bird of paradise) – what more can one ask of late autumn?
Sow broad beans, radishes, spinach, peas, kale, broccoli, kohlrabi, cauliflower, leeks, cabbages, carrots and lettuce.
Pests and problems
Roses – keep on spraying against fungal disease to stop the plants from defoliating.
Keep a sharp eye on aphids, which will be appearing on new growth, and clear up all fallen fruit and old vegetable plants that have stopped producing.
Keep on spraying conifers against Italian aphids.
Cut back Michaelmas daisies, obedience plants (Physostegia), penstemons, yarrow (Achillea) and chrysanthemums. If their clumps have become too thick, you can divide and replant them too.Water and mulch (with acidic compost) camellias, azaleas, rhododendrons and magnolias.The first spring-flowering bulbs should be up now. Water them well twice a week and start foliar feeding with a water-soluble fertiliser or apply specialised bulb food. Feed sweet peas every fortnight.
‘Lekker’ tree: New trees establish well here during winter. A perfect choice is the evergreen white ironwood (Vepris lanceolata), which is a small tree with leaves that are lemon-scented when crushed. Give other trees a last feeding before winter and keep well watered afterwards.
Gap filler: What about Dietes bicolor (yellow wild iris)? It can always be trusted on to grow in sun or shade and is both frost and drought hardy.
Last sowings: Colour in with African daisies and gazanias.
Quick sticks colour: Plant seedlings of flowering kale and fairy primulas.
In flower now: The queen of the autumn garden has to be the beautiful azalea. These plants prefer slightly acidic soil with filtered sun.
Do this now: Ensure that tender plants will be protected as frost can strike as early as May. Frost bags (easy to use) or frost cloth (sold per metre) must be on your shopping list. Protect the roots of tender plants by applying mulch or compost.
When to water: Irrigation should be done between 9:00 and 15:00. If you have automated irrigation, set the times accordingly.
Hot tip: Cut canna stems and leaves off at ground level and use this material to act as a mulch over the top of the rhizomes.
Tie a knot: Remember Mother’s Day on the 10th of May (mothers need a lot of plants!).
Stalwart colour: Plant Gelsemium sempervirens (Carolina jasmine) and allow it to trail over a smart trellis – it can become a pretty focal point for many future winters with its golden yellow flower trumpets.Double up on warm colours by planting some last-minute spring- and winter-flowering bulbs like daffodils, freesias, ranunculus and Dutch irises, and do not forget the tulips – May is tulip planting month! Add some yellow pansies and violas too.
Create: Doll up large patio containers with calamondin (miniature orange) trees underplanted with oriental veggies like mizuna, pak choi and tatsoi and a herb like thyme (all available in punnets or pots at your nursery). Add splashes of edible colour in the form of calendula.
Hot tip: Hellebores, those old stalwarts of cold gardens, will be sprouting new foliage, so you can remove the old, tatty leaves and give the plants a fresh layer of compost. They will soon be in flower.
Winter colour run: Plant pansies and violas to your hearts content. Remember to feed them regularly with a foliar fertiliser. Keep on deadheading blown flowers and pinching out young seedlings to encourage bushy plants that will stretch your flower harvest.
Fungal foes: Look out for root rot and wilt. All the dew in the mornings will bring on lawn fungus – keep a watch for brown patches. Your local nursery can help with the right products to use.
Hot tip: Plant some bulbs and annuals together in containers that you can move around easily, creating instant spot colour on the patio or in the garden.
Garden graft: Install tree rings around newly planted trees as this keeps water and nutrients contained around the root system.
Jay, Good weather!: Keep on planting out seedlings of alyssum, Iceland poppies, primroses, fairy primroses, Bellis perennis, schizanthus, lobelia and a whole host of other flowers.
Hot tip: Continue to disbud young seedlings to prevent them flowering while too small.
Eat well: Plant out young plants of globe artichokes. For something a little different, plant a mixed herb hanging basket and hang it low and close to your kitchen, for easy access.
Garden graft: Keep on raking the last of the autumn leaves and putting them on the compost heap. Get on top of weed problems now!
Switch off: As it is the beginning of the rainy season it is time to switch off automated irrigation systems and have them checked for leaks or any other problems that you may have experienced over summer.
Lawn tip: To improve drainage in lawns before the heavy winter rains, make deep holes with a sharp garden fork all over the lawn. Fill in the holes by brushing in sharp river sand or old potting soil. Supply a dressing of bone meal or superphosphate to improve root growth. Now is also a good time to lay instant lawn sods or to over-seed damaged areas.
Go for bulk: If your plants are not doing well it is mostly because of poor soil. Invest in a bulk load of compost to add to all planting areas. Do not dig it in, just spread it out on the surface to be gently worked in by micro-organisms. Keep thick layers of compost away from the main stems of plants, as it can cause rotting. Bulk composting should be done twice a year for perfect soil.
Tame the jungle: Clean up overgrown beds and add more foliage colour like crotons – their already bright leaves will deepen and become even more jewel-like in colder months. If your shady areas are still dull, brighten them up with Plectranthus ‘Mona Lavender’ and perennial and bedding begonias.
Go ballistic!: Use the cooler weather to fill up window boxes and hanging baskets with instant colour bags and winter-flowering seedlings to enable you to enjoy lots of pretty flowers up close and personal. Look no further than trusty petunias and dainty, but powerful calibrachoas (which resemble miniature petunias). They love dry seasons and grow fast.