What to do in the garden in August

Keep your hedges in tip-top condition towards the end of summer.
Image source: Pixavril

With summer unfortunately drawing to a close, there’s a lot to do before autumn sets in. Make August a productive month!

Plants and Flowers

Protect your dahlias from summer showers
Image source: FMB
  • Stake any tall or top-heavy Dahlias and Lilies to protect them from the wind and rain.
  • Prune your Lavender plants, Helianthemum and other summer-flowering shrubs after they have finished blooming.
  • Prune your climbing roses and rambling roses as soon as they have finished flowering, unless they are repeat-flowering, in which case leave them.
  • There is still time to prune your Wisteria by cutting all the whippy side-shoots back to five leaves from the main stem.
  • Finish dividing your Bearded Iris now to allow them time to establish before winter.
  • Water your Camellias, Azaleas and Rhododendrons well with rain water to ensure good bud-set this year and a spectacular spring display next year.
  • It may seem a long way off but now is the time to think about which spring bulbs and perennial plants you would like for your garden next year. Order your plants online now ready for autumn planting.
  • Give your hedges a final trim before growth slows down.

Fruit and Veg

August is the month for harvesting onions
Image source: Inga Gedrovicha
  • Watch out for the leaves of garlic, onions and maincrop potatoes turning yellow – this means they are ready to harvest!
  • You can plant your Christmas potatoes now ready for harvesting in December. They’ll need to be kept somewhere frost-free or covered with horticultural fleece during cold weather.
  • Keep feeding your fruit trees, soft fruits and vegetable plants in containers every two weeks for continued healthy growth and cropping. Use a high potash fertiliser, such as tomato feed, for fruits and fruiting vegetables (peppers, tomatoes, cucumbers) to encourage good cropping. Leafy vegetables benefit from a basic balanced fertiliser, or one that is high in nitrogen.
  • Tidy up your strawberry plants and remove any straw surrounding them. This will help prevent pests and diseases building up.
  • Cut back any fruited raspberry canes on your summer raspberries. The new green canes should be left and tied in to a support for fruiting next year.
  • Pinch out the tips of your runner beans once they reach the top of their support. This will encourage more side shoots and flowers to grow lower down on the plant enabling easier picking.

What’s your main job to do in August? Let us know in the comments below, or share them with us over on our Facebook page.

Van Meuwen

Author: Van Meuwen

Horticultural mail order specialists. Working hard to bring you the best quality well-established plants as well as exciting new varieties.

9 thoughts on “What to do in the garden in August”

    1. Hi Barbara,
      Winter cabbages and greens like spinach will overwinter well. Try growing under cloches for extra protection.
      Thanks and good luck with your veg.

  1. I HAVE DECIDED THAT ALONG WITH SOME (SEEMINGLY) GREAT LOOKING COMPOST AT
    THE END OF OUR GARDEN THAT I WILL MIX EQUAL PARTS OF THIS GREAT LOOKING COMPOST WITH SOME BOUGHT BAGGED MANURE AND SPREAD IT ALL OVER. ESPECIALLY BENEATH MY NOW HEALTHY LOOKING FUSCIAS, ROSES, LILLIES, RED HOT POKERS, NEWLY PLANTED BERRY BUSHES AND ANYTHING ELSE AND EVERYTHING ELSE.
    PLANTS/PLANTING AREA SO THAT THIS COMING SPRING AND HOPEFULLY NEXT YEAR I WILL HAVE MADE MY LIFE A BIT EASIER. ALSO THE SOIL WILL BENEFIT FROM SOME
    ROUGHAGE AND MAYBE THE WORMS MIGHT COME BACK.
    I AM GOING FOR BAGGED MANURE AS I HAVE HAD THREE SEASONS OF TERROR IN THE FORM OF DANDELIONS AND OTHER WEEDS. AM JUST ABOUT ON TOP OF THE WEED, I THINK, BEFORE MORE BABIES ARRIVE. COW MANURE IS GREAT IN THE GROUND BUT PERHAPS TOO MANY SEEDS IN IT FOR ABOVE GROUND. IF I CAN GET HOLD OF PONY POO (WITHOUT THE STRAW) I HAVE FOUND THIS BECOMES SOIL MUCH BETTER (IE: BREAKS DOWN INTO SOIL NICELY). IF I CAN GET HOLD OF A DECENT AMOUNT I SHALL POP ONTO SOIL TO COVER AREA WHERE MY DAFFODILS GROW.

    I DID USE SOME WOOD SHAVINGS FROM MY WOODTURNING CLUB TO PUT OVER THE GROUND WHERE MY NEW BLUEBERRIES WERE PLANTED. I FOUND THAT THEY DID INDEED PREVENT THE WEED AND ALSO IN THE VERY HIGH WINDS THAT WE EXPERIENCED OVER THE END OF LAST YEAR THAT THEY DID NOT BLOW AWAY. MY LOCAL WOOD CHIP SUPPLIER HAD ALL OF HIS WOODCHIPS LAID IN HIS YARD BLOWN AWAY! I WAS GOING TO
    TRY MULCH OF WOODCHIPS ….. I MIGHT YET EXPERIMENT AS SOME PROTECTION COULD BE REQUIRED THIS WINTER???? IF IT IS AGAIN A CHILLY ONE.

  2. MY PLUM TREE EXPERENCED SILVER LEAF THIS YEAR, WHAT CAN I DO TO SAVE TREE

    HOW DO I PREVENT SILVER LEAF? THANK YOU.

    1. Hello. Silver leaf is a fungal infection which is spread particularly during the winter months. For this reason you should always prune Cherries, Plums, and any other Prunus species in summer rather that winter.

      Cut back any affected growth to around 15cm (6″) beyond the infected wood. This is best done on a dry day. You will need to burn the prunings or get rid of them in your general waste. Don’t add them to the compost heap as this will spread the spores further still.

      Feed and water the tree to help it recover and provide a mulch of well rotted manure or garden compost in autumn. Take care to not mound any mulch around the base of the stem. If you notice any fruiting bodies on the main stem over the autumn then I’m afraid that it would be best to remove the tree entirely.
      I hope that this helps you.

  3. Hi i have 4 standard oleanders, i purchased them last year. But i am a learner gardener and i have been trying to find out how to look after them.
    they are in big pots.The problem i got is the branches have grown and they are not supporting themselves if i didnt tie them up the branches would snap off, also they are not flowering very well at all last year i had loads and loads of flowers this year i only got a few and there not fully opening there falling off before they do,HELP PLEASE as i payed good money for these beauties.Do i have to prune them or what if so how and what to do please thank you

    1. Hello
      Oleander does have a naturally ungainly habit so you will need to prune it to keep it in a good shape. If they are being grown as standards then you will need to prune the main stems back by half their length, and any remaining laterals that are shooting from the main stems can be reduced to about 10cm. This is best done now between late summer and autumn.
      Please take care when you prune them! They have toxic sap so you will need to wear gloves and cover your skin completely whilst pruning them.
      I hope that this helps you.
      All the best

  4. I have bought several dwarf fruit trees for growing in pots on my sunny patio. The two cherries have been attacked both by insects and mould, although I cannot discover what has been attacking them. Any advice on care, and especially pruning, would be much appreciated. They have all settled into their new homes well. (Pear x 2, Apple, Cherries x 2, Blueberries x 4).

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