What to do In August

Tips for RHSI Members

August is a funny month in the Irish garden – high summer one minute, monsoon the next! But there’s still plenty to do, whether you’re tidying, harvesting, or planning ahead. Here’s your handy RHSI member checklist for late summer gardening.

Flowers & Borders
Deadhead for more blooms – especially dahlias, cosmos, salvias and sweet peas. Keep them flowering well into September.
Take cuttings of tender perennials like pelargoniums, salvia (see our article!), and penstemons.
Support top-heavy plants – a sudden downpour can flatten tall perennials like rudbeckia, helenium or phlox.
Sow hardy annuals (like cornflowers, calendula, poppies) for earlier blooms next year.
Lift and divide bearded irises now, while they’re dormant.

Veg Garden
Harvest regularly – courgettes, beans, tomatoes and herbs will keep coming if picked often.
Sow now for autumn and winter crops – think salad leaves, spinach, rocket, turnips, spring cabbage and chard.
Watch for blight – particularly on potatoes and tomatoes. Remove affected foliage immediately.
Keep watering – especially in raised beds, greenhouses, and containers. Rain doesn’t always reach where roots need it.
Dry herbs for winter – now’s the time to cut and hang bunches of thyme, oregano and mint.

Trees, Shrubs & Lawns
Trim hedges like box, privet or yew before growth slows.
Summer prune trained fruit trees (espaliers, cordons) to improve airflow and fruiting.
Plant evergreen shrubs – if the soil is moist enough, you can get a head start on autumn planting.
Aerate compacted lawns if there’s a dry spell. Feed if you haven’t yet.
Water new plantings during any dry spells – especially young trees or hedging.

General Jobs & Planning Ahead
Collect seeds from poppies, nigella, aquilegia and other cottage garden favourites.
Prepare for bulb planting – order your spring bulbs now while stocks are good.
Weed while you can – August growth is rampant, but weeds pulled now won’t set seed.
Check supports and staking after windy days.
Plan your autumn colour – think asters, sedum, ornamental grasses and Japanese anemones.

Don’t Forget:
Keep a notebook or photos of what worked (or didn’t!) this year – August is a good time to reflect.
Visit gardens for inspiration – many are looking glorious right now. See our Partner garden page
Enjoy it! The evenings are still long, and the garden at this time of year has a wonderful wild richness.