Garden Shed: August

August and we are at the peak of the growing season. Although holidays may be on your mind, there is quite a bit to keep you busy in the garden even if it’s keeping plants watered if the sun shines and we have a break from rain.


By trimming now, plants have time to ‘green up’ again.  Formal hedges are an obvious starting point. Yew trimmed now will need no further cutting until next year.  The same applies to other conifers – either hedges or stand-alone plants. If you prefer to cut hard once a year on your hedges, do it sooner rather than later to avoid bare patches. However if you take great pride in your hedges and cut them regularly, the density will be such that this will not be a problem.

Shears or hedge trimmer must be sharp to avoid ripping rather than cutting.

Any golden or bright green conifers that are growing in a chalk soil may have a bleaching in some of the foliage. By applying sequestered iron, you will return the colour. Also any large conifers growing in containers will need feeding with a general-purpose liquid food to retain their colour.


Layer carnations and pinks during August to provide new stock for next year. Train clematis, honeysuckle and wisteria before the shoots become unmanageable. Lavender may need trimming. Penstemons need their flower spikes cut down. Roses can still be budded to supplement next year’s stock. Sweet peas need watering well with a regular dose of liquid manure. Remove all dead heads in your spare moments. If moving tulips, lift and store on their sides in trays.

If you want to carry on planting through August, sow Annuals like antirrhinums, pansies, violas, and Iceland poppies. For flowering next spring, sow early in the month. Sow ten-week stock towards the end of the month.

Plant Colchicums for autumn flowering, they come in various flower shapes and colours. Plant in well drained soil, 4″ deep and about 8-10″ apart for naturalising in either shade or full sun.

Crown Imperials are a good ‘showy’ summer flower. Plant bulbs in very well drained soil in full sun, 4 times there size deep. Grow in containers if there is a risk of the soil becoming too wet over the winter. They will have heavy, tall flower spikes, so the container will need to be pretty heavy to avoid it falling over – a half-barrel or sturdy planter would be ideal.

Planning ahead

Plant out cuttings of carnations and picotees. Pot others and keep aside for use as replacements if necessary. Thin perennial seedlings and replant the removed plants in other positions in the garden. Divide and replant spring flowering perennials. Look for places to plant bulbs in the lawn for next spring.

Continue watering plants under glass and keep a look out for pests and diseases as they are at their most prolific at this time of year.

Azaleas need re-potting. If time allows, de-bud the Chrysanthemums. Climbing plants need cutting back. Pelargoniums need to be stood outside to ripen the wood. Sow Annuals under glass such as clarkia, cyclamen, pelargoniums, schizanthus. Sow stocks for winter flowering.


August is the cutting month. All kinds of hardy and bedding plants can be struck in sandy soil this month. You may care to use rooting powder, but it is a matter of choice. Roses such as the Bourbon China, Hybrid Perpetual and Noisette may be struck. Viola cuttings may be taken and struck. The Saxifrages should have their side shoots taken off and planted in borders or pots.

The Vegetable Garden in August

Remove the remains of harvested crops and put on the compost heap.

Plants, like French beans and onions, can be left for next year’s seed. Asparagus beds must be kept free of weeds. Cut bearing tips if seed is not required . Broccoli will require plenty of water when the heads are forming. Cabbages can do with having a pinch of sulphate or ammonia hoed in to make them heart up. Celery should have any side shoots cut off and given water and liquid manure. Earth up celery and leeks. Ridge cucumbers, tomatoes and marrows need water as required during hot weather. Harvest marrows when about 8 inches (20cm) long, the early cut will improve the yield. Collect herbs for storing.

Dig up and dry in the sun early potatoes you want for next year’s seed. Runner beans should be stopped when they reach the top of the poles and the fruit harvested when formed and not left on the vine. Start harvesting shallots, onions and garlic.

Sow cauliflowers for summer and onions for next year with radishes, red cabbage, spinach and turnips. Start Cauliflower seeds in a frame. Uncover as soon as the seed is up in order that they may harden off.

Cucumbers under glass may need some bottom heat and a dressing of sulphur to prevent mildew. Plants started now should fruit until Christmas. Melon beds need to be dried off as the fruit ripens.

The Fruit Garden in August

Start pruning trees. Protection bands round tree trunks will give an idea of what pests are in the neighbourhood. Apples, pears and plums may need the fruit thinning out if the crop is heavy and branches are starting to bow. Apricots, peaches and nectarines need as much sun as possible. Cut down old canes after fruiting on loganberries and raspberries. Remove unwanted strawberry runners and the old straw from round the crowns. Make new beds for the runners.

Spray peaches and nectarines under glass and given good ventilation. Keep fruit trees in pots out in the open until after the fruit has been picked. Strawberries to be used for forcing should be planted into 6-7inch (15cm) pots and given plenty of water.


Turnips may need the flies kept in check by dusting with slake or ground lime. Protect fruit from wasps and birds as it ripens. Trap pests like earwigs and snails. Watch out for wasps and mice.


Finally, spare a thought for the poor fish in the pond. Instead of just dropping the end of the hose in the pond to top it up during the hot weather, attach it to something and allow it to splash into the water. This helps to oxygenate the water more effectively.

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