Monty Don reveals the most important gardening jobs for August

The growing season for many of us this year has been somewhat unpredictable and with late frosts well into May, cooler wet weather throughout June, and high winds in many areas of the UK during the month of July. Leaving August gardens looking a little tired, as Monty Don describes “this is clearly a kind of ending and the demands of spring and summer growth start to show.”

The month of August, carrying the weight of summer and the seeds of winter is abundant in ripening fruits, bright displays of sunflowers, zinnias, canna lilies and dahlias with much of the garden coming into full fruition, however, the days are growing shorter, the evening’s cooler, and the ground beginning to slowly clear. There is a sense of exhaustion in the garden, so now is the time to reinvigorate and revitalise your surroundings.

Trim Back Hedges

Monty Don advises beginning with a trim of any hedges, holding them to size and shape, as many of the nesting birds have fledged. “summer pruning results in slower, less vigorous regrowth than a winter trim so clip hedges to the height and shape that you wish them to remain for the rest of the year.” Making sure to shape the hedges with a slight ‘batter’ – an outward slope from top to bottom – preventing the lower area of the hedge from being shaded by any bushy growth above. 

Deadhead Flowers Daily

Next on the agenda is to deadhead flowers daily. As Monty recommends “nothing else is so effective in keeping summer flowers from lasting as long as possible” Dahlias, margarites and delphiniums all benefit greatly from a morning/evening spruce. Lavender should also receive its annual pruning to avoid woody, leggy growth. So as soon as you see your flowers begin to fade in August, “cut back hard to a good compact shape but be sure to leave some new shoots on each stem – lavender will often not regrow from bare wood.”

Move Herbaceous Perennials

After summer perennials have enjoyed a full bloom, this month is an excellent opportunity to move any herbaceous plants into new desirable locations. The benefit of doing so in august is to see clearly how they will look with their new surroundings whilst also proving less stressful for the plants. “Then, having moved them, it is a good idea to cut them back so that the plant has a rest and can recover from the trauma of being uprooted” Monty advises.

Take Cuttings

Finally, before the growing season is out, be sure to take cuttings of any of your favourite roses, buddleja, fuchsias or hydrangeas. Choose flowerless healthy, strong, straight growth and strip away all lower leaves and side shoots so that approximately an inch or less of foliage remains. With a sharp, disinfected knife or secateurs, cut the bare stem and plant immediately in a gritty/sandy compost mix or perlite.

Any newly buried cutting must not dry out and have free-draining compost. So water sparingly but regularly. A tip is to spray water into a clean, clear plastic bottle and place this over the top of the cut stem. This will help to create an ideal humidity for growth. Alternatively, you can mist the foliage as it grows to prevent the leaves from drying out. Once roots begin to form, your cutting will require more nutrition, so pot up into a more nutrient-dense compost.

Your cuttings will need to bath in the warm sunlight of a windowsill or orangery but avoid full sun and south-facing windows which can cause scorching. Monty explains that “most cuttings taken at this time of year will take between 4 and 6 weeks to produce viable roots but you know that the roots have formed when you see fresh new growth or, when lifting the pot, see thin roots appearing from the bottom of the pot. At that point, the cuttings can be removed from the pot and potted on individually into fresh peat-free potting compost and put aside over winter before planting out next spring.”