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Updated : 21/9/2014

To do in December

This is a busy month for all, but ensure your tasks are completed early to allow you time to enjoy your garden over the festive season. The second flush of roses and the early Summer flower annuals are just beginning to open. Hydrangeas, Liliums, Day Lilies and Agapanthus add to the beauty of the garden.


Continue watering in dry weather. Feed twice a month with a liquid fertiliser. Dead-head regularly. Fill in any gaps if necessary. Be on the look out for the tell-tale signs of red spider - a fine web that is visible on the undersides of leaves. The foliage turns silver-grey and later brown in colour. Put out bait for slugs and snails.

The following quick growing summer flowering annuals can still be sown:

Bedding Dahlia
Dwarf Marigold
Eschscholtzia califonica (Californian Poppy)
Iberis umbellata (Candytuft)
Tropaeolum majus (Nasturtium)

In cool areas seed of winter-flowering annuals, which have a long growing season, can still be sown:

Ornamental kale


Amaryllis belladonna - in the summer rainfall areas, lift and divide if necessary.

Amaryllis family - watch for attack by the amaryllis caterpillar.

Gladioli - continue planting to ensure a succession of flowers.

Nerine - these indigenous bulbs can be planted this month for Autumn colour.

Crinum - cut-off the faded flower heads. Save the fleshy seeds and plant on the surface of the soil in small containers.

Irises - divide overcrowded tall bearded hybrids.


Any of these perennials that were not sown last month can still be sown now:

Achillea millefolium (Yarrow)Penstemon
Alcea rosea (Hollyhock)
Aquilegia (Columbine)
Aster novi-belgii (Michaelmas daisy)
Bellis perennis (English daisy)
Bergenia cordifolia
Begonia (all types)
Cerastium tomentosum (Snow-in-summer)
Chrysanthemum maximum (Shasta daisy)
Digitalis (foxglove)
Felicia amelloides
Gerbera jamesonii (Barberton daisy)
Heliotropium (Heliotrope)
Hypoestes (Polka dot plant)
Limonium perezii (Statice)
Lobelia cardinalis
Nepeta (cat mint)
Physostegia (Obedience plant)
Rudbeckia (Gloriosa daisy)
Viola odorata

Acanthus - lift and divide if necessary. Cut back old leaves and flower stems to ground level. Feed each clump with a handful of 2:3:2 fertiliser around the base. Mulch with compost. Water once a week during dry weather.

Delphiniums - Water well every second or third day during dry weather. Feed twice a month with a liquid fertiliser.


Continue with a regular spraying programme to combat fungal problems. Feed with 8:1:5 fertiliser or an organic equivalent. Mulch with well-rotted, old manure around each plant, keeping it well away from the stem.


Mow fine grass once a week and kikuyu twice a week. Lift the lawn-mower blades to allow the grass to grow slightly longer - this will give the roots protection from the heat of the sun and from drying winds. To transform your lawn into a lush, green carpet, feed with a high nitrogen fertiliser or L.A.N. and water well.


Semi-hardwood or half-ripe cuttings of Hypericum, Fuchsia, Hydrangea, Pentas, Pelargonium and Lavender can be taken this month.

Pot up plantlets, which have developed on Dietes and Day Lily flower stems. Layer Carnations and Dianthus.


Water every week during dry weather and mulch the ground with compost.

Camellias - feed each bush with about 30 grams of magnesium sulphate (Epsom Salts). Dissolve this in 5 litres of water and apply as a liquid.


Amaryllis (Hippeastrum) - continue feeding every two weeks with a liquid fertiliser to build up the bulb for the next season.

Wipe dusty leaves. Spray the leaves of foliage plants in hot, dry weather. If this is done outdoors, ensure that the plants are in the shade - the leaves are sensitive to the sun and will burn easily. Do not wet grey, hairy leaves.


Lettuces - when planting in Summer choose heat tolerant varieties.

Tomatoes - spray against blight once a week and after heavy rain.

Onions - harvest.

Beans - pick two or three times a week and sow small batches of seed about once a month for succession.

Cucumber family - splash bait on the leaves of all members of the cucumber family (cucumbers, marrows, melons, pumpkins) to protect the fruit from pumpkin fly.

Potatoes - harvest baby potatoes. They should be ready for lifting once the plant has flowered.

There are numerous vegetables that can be grown from seed. These are region specific. Ask your local nurseryman for advice.


Continue to spray for fruit fly and coddling moth, being very careful to observe the necessary safety period. Collect and dispose of all fallen fruit to prevent fruit fly breeding. When the fruit has been picked, feed with a 6:1:5 fertiliser at the rate of about 100 grams for young trees and up to 200 grams for older trees. Excessive leaf growth shades the tree causing poor fruit development. Reduce the amount of fertiliser if this occurs.

Citrus - feed each tree with 3:1:5 fertiliser spread over the root area, starting at least 10 centimetres away from the trunk and going out to just beyond the drip line of the branches. Mulch and water well every three weeks in dry weather.

Grapes - keep well watered as fruit swells.

Berries (boysenberries, raspberries and youngberries) - when the bushes have finished bearing cut the old fruiting canes down to ground level. Tie the new canes on to the supports to take the place of those cut down.

Strawberries - feed with liquid manure when the last fruits have been harvested.


Prune spring flowering shrubs such as Weigela and Philadelphus. Prune climbers like Jasmine and Petrea to maintain a compact shape. Cut back Santolinas and trim Lemon Verbena after flowering.

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