Gardening in May is like putting a baby to bed… You clean it up by removing all the refuse, feed it to make it strong for the 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.
Your garden during the month of May
The leaves of heavenly bamboos (Nandina domestica and N. ‘Pygmaea’) will start turning a gorgeous rusty red. Camellia sasanqua hybrids, which can tolerate more sun than the japonicas, will be in flower. In the indigenous patch there’s loads of eye candy with wild dagga, ribbon bush, Cape honeysuckle and the very elegant Strelitzia reginae (bird of paradise) all in flower — what more can one ask of late autumn?
Top tip for food gardening
- Sow broad beans, radishes, spinach, peas, kale, broccoli, kohlrabi, cauliflower, leeks, cabbages, carrots and lettuce.
Tips for pests and problems
- Roses — keep on spraying against fungal disease to stop the plants from defoliating.
- Keep a sharp eye on aphids, which may be appearing on new growth, and clear up all fallen fruit and old veggie plants that have stopped producing. Keep on spraying conifers against Italian aphids.
- Cut back Michaelmas daisies, obedience plants (Physostegia), penstemons, yarrow 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 at this time of year. 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) — a small tree with leaves that are lemon scented when crushed. Give other trees a last feeding before winter and keep them well watered afterwards.
- Last sowings: Fill in gaps and add colour with African daisies and gazanias.
- Quick sticks colour: Plant flowering kale and fairy primula seedlings.
- In flower during May: The queen of the autumn garden has to be the beautiful azalea. These plants prefer slightly acidic soil with filtered sun.
- Ensure that tender plants are 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 9am and 3pm. If you have automated irrigation, change your times accordingly.
- Cut canna stems and leaves off at ground level and use this material as mulch over the top of the rhizomes.
- 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. Add splashes of edible colour in the form of calendula.
- 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.
- 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.
- Keep on planting out seedlings of alyssum, Iceland poppies, primroses, fairy primroses, Bellis perennis, schizanthus, lobelia and a whole host of other flowers.
- 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’s 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 aren’t doing well it’s probably because of poor soil. Invest in a bulk load of compost to add to all planting areas. Don’t 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. Hot tip: Add drifts of arum lilies in bare spots with morning sun between other plants taking a well-deserved rest after summer. Both the leaves and flowers are something to behold.
- 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.