Gardening News, Advice, Tips and Jobs For August 2023

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News, Tips, Advice and Jobs August 2023


By Howard Drury


August - and a time for summer holidays.  But will it be hotter or cooler than the record-breaking 40.3C experienced on the 19th of July this year? Over the next few days I will be tailoring my jobs for August and bringing you all the latest news, trends and ideas, so please do call back - regularly!

Wet wet wet is my message this month so do adjust your gardening accordingly, it is hard to believe how dry we were until the beginning of July, with saw on one evening our garden receive 39 mm of rain in just two hours and now in to August, and it still rains day after day.

Box blight is a major problem, target water to root areas avoiding splashing the foliage, don’t clip too short, and you may feed with a special box feed or a seaweed-based feed. Fungus Fighter contains chemicals said to control Box Blight, it's on the label, so it must work! By law!

Most garden centres are experiencing huge price rises  and many garden insecticides are due to be withdrawn from sale from 1st October 2023, so you may see your favourite insecticide is no longer available. Retailers have six months to sell stock and end users 12 months from the withdrawal date.


The best advice must be to garden with the weather, it is difficult to keep plants alive in any situation when temperatures day after day were in the upper thirties, this means delaying many jobs such as seed sowing, as the forecast is predicting continuing dry weather until the end of July.


 I will add these as we get nearer to August and update them as the month progresses. The most important one is to take pictures or make notes of the plants that have thrived, survived or died during the two very hot spells this month.

The Ornamental Garden

August is a good month to check plant and tree labels and renew those which have faded or become brittle.  It is also a good month for bulking up the compost heap!

Baskets, tubs and window boxes should be kept well-watered and given a dose of fertilizer to maintain flowers through to the first frosts.  If you are going on holiday now, it is a good ideal to move containers into the shade.

Continue dead heading and removing seed pods where they are not required on plants in beds and borders.  Supports and spent flower stalks can also be removed from plants which have finished blooming.  Late flowering border plants, such as Michaelmas daisies, will appreciate a liquid feed.  In addition, Michaelmas daisies will require staking and should be sprayed against mildew.

Geranium cuttings can be taken from healthy stock, plus cuttings of Penstemons and Calceolarias, and there is still time to take cuttings or pipings of pinks.  The border carnations and Dianthus layered last month can now be planted out.  New border carnations and pinks should be ordered, ready for planting in the autumn, and the bed prepared for them by digging and manuring.  Lime should be added if the pH is below 6.5.

Finish disbudding early Chrysanthemums by rubbing out a few buds at a time, then apply a liquid feed.  Where large dahlia blooms are required, these too should be disbudded - but not pompon varieties - and then given a liquid feed and kept tied to their stakes.  Keep a look-out for earwig damage and set straw traps where necessary.  Watch for gladiolus thrips and control when necessary.

As sweet peas reach the top of their canes, they should be lowered and retrained.  Continue to pick the flowers and control weeds by hoeing if a mulch has not been applied.  If cutting gladioli flowers for indoor decoration, remember to leave at least four leaves on the plants.  Now is also a good time to cut Statice, Helichrysum and Acroclinium for drying to use in winter decorations.  They should be gathered and hung upside down in a dry but airy place.

Autumn crocus and colchicums should be planted as soon as possible, and Madonna lilies planted with a little sand beneath each bulb and only 1in of soil above.  Complete planting or re-planting bearded irises, examining the lifted bulbs and burning any which show signs of rotting.  Bulbous irises should be ordered now for planting in the autumn, and it is a good idea to begin choosing and ordering spring-flowering bulbs.  In milder areas, Brompton stocks can be planted outside now, otherwise over-winter them in a cold frame.  These are grown as biennials for flowering next spring.

If you have sown winter pansies into a nursery bed in anticipation of transplanting them in October, you'll probably find they are ready for thinning now.  Cuttings of pansies and violas can also be taken, and violas should be trimmed back and top-dressed.  During this month hardy annuals may be sown in nursery beds to over-winter and, as soon as they are ripe, Meconopsis and Primulas seeds can be collected, sown and placed in a cold frame.

Cuttings of alpines such as Helianthemums, Dianthus, Achilleas and Saxifrages, can be taken now.  Well-prepared ground should be covered with about 0.5-1in of sharp sand, given a light watering and the cuttings inserted and covered with a shaded frame or cloche.  Alpine cuttings taken earlier in the year are probably ready for potting.

Summer flowering shrubs, including Weigela and Philadelphus, can be pruned after flowering by removing overcrowded and old branches to ground level.  Continue to spray roses and to remove blooms as they fade, but stop feeding.  When rambler roses finish flowering, they should be pruned by untying all the stems from the trellis and cutting off, at ground level, those stalks which have carried flowers.  Apply sulphate of potash to established roses to ripen the wood for the winter.  Orders for new roses ought to be placed now, so they can be delivered in time for November planting.

Continue to trim fast-growing hedges and keep the hedge bottoms free of weeds and rubbish.

Cuttings of shrubs such as Callicarpa, Cistus and Escallonia can be taken during August by pulling off side shoots complete with a heel of old wood, while rhododendrons should be propagated by layering.  The layers will root sufficiently for planting out separately in two or three years.  Lavender cuttings, 4-6ins long, may also be struck outdoors.  Remove the lowest leaves from stems and inset the cuttings close together for two-thirds of their length.  Other herbs may also be propagated by cuttings this month, including bay, hyssop, mint, rosemary, rue and sage.  Chives should be divided every four years by lifting the clumps and cutting them with a sharp knife before replanting about 12ins apart.  Dill and fennel seeds can be collected and dried.

With catalogues arriving and orders being posted (or perhaps e-mailed), time should be spent planning any new beds and borders.  Ideas are best put to paper, preferably to scale on graph paper, then preparation of the new sites can begin.

The Lawn

Hopefully it will still be possible to mow the lawn in between the games of French cricket and the encampment of play tents!  In dry spells it will be necessary to water, and ideally you should inspect the lawn and give a final application of weedkiller if control is needed.  Sites prepared for new lawns should be given an application of a pre-seeding fertilizer.  The grass seed can be sown a week later.

The Vegetable Garden

Keep beans and peas watered and mulched.  In dry weather runner bean flowers sometimes do not set proper but a light spraying with water each day should help to encourage a good set.  Continue picking beans every few days before they become old and stringy.

Potatoes are likely to need spraying with a copper fungicide to avoid blight.  They should be lifted towards the end of the month, when the skin has set.

Leeks and celery will require earthing-up and where celery fly is troublesome it may be necessary to spray with an insecticide recommended for use on vegetables.  Endives also need blanching.  This can be done simply by tying the leaves loosely with raffia and placing a flower pot over the plant.

Winter lettuce such as 'All the Year Round' can be sown now, either in sheltered spots or in a cold frame, and spring cabbage can be sown 0.5in deep in drills 6ins apart.

By the third week of August, in order to form bulbs early next year, Japanese hardy onion seed can be sown.  Any onions currently reaching maturing should be encouraged to ripen by bending over the tops and partially lifting the bulbs.

Continue to feed outdoor tomatoes and remove some of the lower leaves to assist the ripening of the fruit.  And, thinking of ripening, check the sweet corn.  If the tassels are showing signs of withering and the cob exudes a milky liquid when squeezed, it is ready for picking.

The Fruit Garden

Raspberry canes can be pruned once they have finished fruiting.  Retain only half a dozen of the strongest new canes on each plant for next year's crop, and tie in new canes to the wires.  Blackcurrants also need pruning by cutting, to ground level, those stems which have fruited.  The bushes will benefit from a feed of sulphate of ammonia, but use with care.  It can cause scorching.  And, while you are working in the fruit cage, it makes sense to check over the netting and repair as required.

New strawberry plants, certified virus-free stock, can be planted 18ins apart with 24-30ins between the rows.  Runners should be removed when they begin to form on these plants.  You might also consider potting-up some of the best plants into 6in pots for forcing under glass in spring.  For the moment, the pots can be plunged into soil outside.

Keep an eye on the grapes.  Mildew can strike quickly and where it is spotted, affected bunches should be removed.

Trees of early apples can be tested for ripeness by lifting and gently twisting the fruit.  If they come away readily, the fruit is ripe and ready for picking.  Cordon and espalier trained apples and pears can be exposed to the sun by moving back the foliage.  Peaches and nectarines can also be helped to ripen in the same way.  Remember to remove any side growths on peach and nectarine trees.

Conservatories, Glasshouses, and other protected situations

Keep the greenhouse or conservatory well ventilated to discourage mildew.  Damp down the floor and staging regularly in hot spells, and check and renew shading where necessary.  This is also a good month to check over the greenhouse or conservatory for any signs of damage, so that repair work can begin before the onset of cold autumn nights.  You might even consider the advantages of installing a heating system if you haven't already got one.  Existing systems should be tested to ensure they are running properly before they are required.  Give yourself plenty of time to sort out repairs.

Pot-on any plants, such as cinerarias and primulas, which have become pot-bound.  Cineraria is particularly at risk of damage from leaf miners and should be sprayed if necessary.  Similarly, it is important to watch for signs of botrytis on double-flowered begonias.  Spray infected plants with a systemic fungicide.

Cuttings of many houseplants, including coleus, begonia, Crassula, Selaginella and Tradescantia, can be taken this month.  It is also time to take cuttings of Jasminum polyanthum, using a closed case, propagator or polythene bag, along with cuttings of heliotrope, fuchsias, pansies, geraniums and regal pelargoniums.  Any cuttings taken previously, and which have already rooted, can be potted on without delay.

Seeds of antirrhinum, clarkia and godetia may be sown for flowering next year and consider making a sowing of schizanthus as they provide as wonderful display of colour in spring.

If you fancy flowers at Christmas - and who doesn't - specially prepared hyacinth and narcissus bulbs should be planted as soon as possible.  Freesia bulbs can also be potted-up and kept in the cold frame until November when they may be brought, a few at a time, into a warm greenhouse to supply a succession of flowers in winter and early spring.  Now is also the time to bring cyclamen in from the cold frame and start them into growth, avoiding repotting unless it is really necessary.  Seed can be sown to provide new cyclamen plants.

Amaryllis bulbs will have completed their growth and the leaves should have died down.  They can be stored in their pots under the staging until spring, keeping them frost-free but not above 50 degrees F, as this will encourage bud development.  Gloxinias should be gradually dried off as they cease flowering, and the corms should be allowed to rest through the winter.

Continue to assist the ripening of indoor tomatoes by removing some lower leaves.  Cucumbers should be fed and watered, and sprayed with a systemic fungicide to prevent mildew taking a hold.

Wildlife and Nature

To be added

General Maintenance

To be added

Looking Good This Month


Achillea tomentosa,

Campanula carpatica,

Erodium chamaedrioides and varieties,

Gentiana Farreri,

Geranium sangiuneum,

Linaria pallida,

Linum alpinum,

Lithospernum prostratum and varieties,

Polygonum affine,

Potentilla ambigua,

Statice minuta


Crinium longifolium and varieties,


Lilium Henryi, L. superbum,

montbretia hybrids


Achilleas (including A. folium varieties),

Astilbe arendsii hybrids,


chrysanthemum (early-flowering hybrids),

border carnations, Geum coccineum hybrids,

sunflowers (Helianthus multiflorus and varieties),


Kniphofia erecta,



Iceland poppies,



Sedum maximum,




Shrubs deciduous

Calluna vulgaris and varieties,

Colutea arborscens, C. orientallis,

Erica cinerea, escallonia hybrids,

Hydrangea arborescens grandiflora,

Shrubs evergreen

olearia, spiraea


Clematis (including C. durandii and varieties, C. Hendersonii, C. Jackmanii, C montana Wilsonii),

Lonicera japonica, hybrid roses (also multiflora and musk),

Trachelospermum divaricatum


Aesculus californica, Sophora japonica


The information given in this Fact Sheet is provided in good faith. It is however of necessity general information and advice on the topic. Howard Drury will not be under any liability in respect of the provision of such advice and information, and you are strongly advised to seek independent advice on any particular gardening problems or queries you may have, preferably from experts who can (when appropriate) inspect the problem before providing advice.

© 2022 This material has been produced by Howard Drury and must not be reproduced in part or full without the written consent of Howard Drury, Kings Heath, Birmingham, B13 0SJ.

JHD/ 24.02.2022

Image is designed and maintained by Darren Hodson © 2022, The Drurys