Garden Care in May

What to Do

May is the perfect month to start a compost heap. Your compost should be ready in a few months, just in time for you to use in your spring garden.

If you’re thinking about any serious winter pruning, then May is a good month to prepare by sorting, sharpening and cleaning your secateurs, loppers and pruning saw.


Prune Apricot trees as soon as possible before the very cold weather arrives. Remember to seal all pruning wounds with Steriseal. This assists to prevent the entry of a nasty disease, called bacterial gummosis, into the open wounds.

Remove yellow leaves from brassicas such as brussel sprouts, cabbages, cauliflowers and broccoli to prevent disease.

Fill your bird-feeders with a mixture of fruit and seeds to bring wildlife into the garden. In areas with no winter rainfall, make sure your birdbath is filled with fresh water.

Watering whether by hand or an irrigation system should be done after nine in the morning and completed by three in the afternoon – wet plants will freeze!


Some Azaleas are already starting an autumn flush. Azaleas, Camellias, Gardenias all need attention now if they are to bloom in winter and spring. Make sure that you give them deep regular watering so that their buds develop properly. If they are allowed to dry out too much the buds abort and your flowering will be delayed.

Mulch your open garden beds or cover them with a creeping groundcover such as indigenous Geramium incanum or Arctotis to prevent the soil from drying out. Make sure that you keep your roses mulched. They will now need a rose fertiliser rich in potassium which will also help harden soft wood before the cold weather.

Water citrus deeply once a week to prevent bud drop.

Reduce watering of pot plants that like to rest during the winter.  (i.e. tuberous plants and ferns). An important note to remember when it comes to your indoor potted plants is to be mindful of heaters in the room, as plants will not enjoy this artificial heat. We recommend moving them into an area in your home, where there are no heaters.

Water features should be cleaned out regularly of fallen leaves.

What to Plant

It’s autumn and the weather has cooled enough to make it the perfect season for planting because new plants require less watering and TLC to develop strong roots and healthy growth. Want to brighten up your garden during the cold months ahead? Pop into your nearest accredited garden centre and get your hands on a few of these beauties:

Winter- and spring-flowering seedlings like Iceland poppy, cineraria, stocks, snapdragons, lobelia, delphinium, gazania, foxgloves, cornflower and larkspur.


Want to attract birds to your garden during winter? Then you should definitely plant winter-flowering fynbos like proteas, ericas and leucospermum. Not only is a fynbos garden indigenous and water wise, it is beautiful too and can be planted in combination with other indigenous species such as agapanthus, crassula and plectranthus to create a stunning display all year round.

Ornamental Kale makes an unusual but stunning winter option for colour.

Carrots, beetroot, cabbage, turnips, spinach and celery should be planted now and if you’re in need of a natural insect repellent you can interplant with Tulbaghia (wild garlic).  Yarrow is a must in every garden.  The secretions of their roots activate the disease resistance of surrounding plants and also deepen the fragrance and flavour of herbs.

This is a great time to plant new roses as it will give them a ‘kick-start” in spring.


What to Sow

Sow Namaqualand Daisies and Californian Poppy seeds in your flowering bed or among your winter veggies. The striking orange is always an eye catcher.

Sweet success with climbing sweetpea seeds. They will grow happily into a topiary cone shape in the garden or in a pot with a metal support in the shape of a cone creating an interesting decorative feature. Check out how to make our Mini-Teepee for your sweetpeas.

You can still sow a last batch of dianthus, pansies, Virginia stocks, calendulas and cornflowers to prolong their flowering season. Sow the seeds straight into the soil as long as the soil is well prepared. Fork and rake over the top few inches, breaking down the clumps, add compost and then follow the sowing guide on the packet.

What to Spray

Have a close look at your indoor plants for signs of pests and diseases. Spray for scale and mealy bug with Wonder Garden Gun. If their numbers are out of control it is best to take the plant outside (in the shade) and spray with Garden Ripcord. Allow the plant to dry off and make sure you bring it in before nightfall. Scale insects on potted palms can be treated with insecticide granules.

Seagro promotes thicker stronger cell walls in plants, which means better resistance to sucking insects and fungal attack. These little pests need to pierce the cell walls to do their damage. If the cell wall is strengthened they will have a trouble getting through the cell walls. Give your plants a good dose of Seagro to help keep these critters at bay.


Lily borer are dreadful pests that eat their way down through the leaves and right into the base of clumping plants such as clivias and agapanthus. By the time they’ve finished their munching, these huge grubs have often completely destroyed the plant. Mix up a solution of low toxic Eco Insect Control SC and thoroughly spray over the leaves. Use some of the remaining spray mix to saturate the base of the plant.

This is a good time to get control of weeds in the lawn and garden. Spread lime and mulch under fruit and evergreen trees and also on the lawn. This will help balance the pH of the soil, as weeds prefer acidic soils to thrive in. Banweed MCPA is for the control of soft broadleaf weeds in newly planted lawns (Do not apply to new lawns less than 3 months old). Hormoban APM and Turfweeder APM will control broadleaf weeds in established lawns. A product called No Weed Lawn is an easy and convenient way to control broadleaf weeds in small established lawns.

Watch out for fungal diseases like rust and black spot on your roses, pelargoniums and geraniums. Spray the entire plant (under the leaves too) with a fungicide like Dithane M45.

Keep spraying conifers with koinor or organic insecticide.

Inspect your lawn for Dollar Spot, a fungal disease that causes yellow spots on the blades of grass. Treat Dollar Spot with Bravo 500.

Tackle snails and slugs as soon as they appear, before they have a chance to breed and cause more damage. Try organic snail bait like Ferramol, or surround precious seedlings with crushed eggs shells, sawdust or coffee grounds.


What to Feed

Feed azaleas and camellias with 3:1:5 fertiliser to ensure healthy plants that will reward you with an abundance of flowers. You can also use this same fertiliser to feed your lawn – just make sure you water the lawn well after you have fertilised.

To keep your citrus trees producing fruit for the next few months, apply a moderate amount of nitrogen fertiliser on the surface of the soil around the trees and water in thoroughly.

Do not forget to give your annuals a regular feed (every third week) to ensure a wonderful winter and spring display of colour. Pop into your nearest accredited garden centre to pick some up.
3:1:5 fertiliser can also be given to your rose bushes to prepare them for the winter months.

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