Summer gardening errors to avoid now

As August arrives, many gardeners are eager to relax in the garden and make the most of its summer splendor, while others are keen to make a start on getting the garden in shape for next year.

August can be a tricky time in the garden, and mistakes made during this period can weaken plants, reduce their flowering, or even risk sacrificing precious blooms altogether. One mistake gardeners frequently make is cutting tired-looking perennials back too early.

While faded foliage can look untidy, many plants are still photosynthesizing and storing energy that will help them survive winter and produce even stronger growth next spring. Many beloved summer flowers, such as peonies, hardy geraniums, salvias, and ornamental grasses, benefit from being left alone for longer so that their leaves can continue feeding the roots.

Being overzealous and removing this foliage too soon can disrupt this important process and lead to a weaker plant that can’t flower as strongly next year. Many spring-flowering shrubs form their buds during late summer and autumn, meaning cutting them back now removes the sensational displays you have been hoping for.

Lilac, forsythia, flowering quince, mock orange, and weigela are best pruned shortly after flowering finishes in late spring or early summer. If your spring shrub has become overgrown and you can’t resist giving it a bit of a tidy, you can remove around one-third of the older stems at the base after flowering, which will enable younger branches to take their place and help you maintain shape without sacrificing next year’s flowers.

When you are pruning, use sharp and clean secateurs. Buying brand new plants only for them to wilt and die before they are established can be heartbreaking. Newly planted trees and shrubs and perennials are vulnerable, especially in summer’s heat, as their root systems are still developing and cannot access moisture that is deeper in the soil.

Just because a plant looks healthy, below the surface it may be struggling, and a lack of attention now can affect flowering and growth next year. Although different types of plants vary in how best to water them, typically it’s best to water once or twice weekly during dry spells and only water in the mornings or the evening, never in the heat of the afternoon.

Don’t assume that just because a plant is in full bloom that it no longer needs nutrients in the form of plant feed, as during the flowering months, plants do continue to benefit from support. Roses, dahlias, containers, and repeat-flowering perennials are exerting a lot of energy to keep producing their blooms, and without feeding, you may lose some flowers or the flowers that are produced may be smaller.

Continuing to feed will enable your plants to enter autumn with strength, too. It’s sensible to use a high-potassium feed to encourage flowering rather than a nitrogen-rich fertiliser, which encourages soft leafy growth. To attract birds to your garden, few draws can be better than beautiful rose hips; they are both beautiful and practical, but allowing repeat-flowering roses to develop hips in August can signal the plant to stop producing flowers.

Remove faded flowers regularly if you would like to encourage your roses to continue flowering into the autumn. The best approach when deadheading roses is to cut just above the first healthy leaf with five leaflets to encourage strong new growth. When late autumn and winter arrive, leave some of the hips later in the year for wildlife once flowering naturally slows.

If you do not regularly deadhead, many summer flowers will stop producing new blooms if spent flowers are left in place. Regular deadheading encourages plants to keep flowering and prevents energy being diverted into seed production. Some of the plants to be most assiduous in deadheading include dahlias, cosmos, sweet peas, penstemons, coreopsis, and scabious, whilst leaving the seed heads on echinacea and rudbeckia will provide gorgeous winter interest and are also a vital food source for birds and other wildlife when winter arrives, and food is more scarce.

In prolonged dry weather, one of the first things to suffer is your container plants, as your pots can dry out remarkably quickly, especially anything planted in terracotta or your hanging baskets. Allowing plants to repeatedly wilt can reduce flowering and permanently stress roots, so it’s sensible to intervene as soon as your container’s topsoil feels dry. You should check your containers daily during hot weather and water thoroughly until excess moisture drains from the bottom.

Adding mulch to the surface of pots can also help reduce evaporation and retain moisture for longer. Many gardeners focus on flowers above ground but forget that next year’s display depends on what happens beneath the surface, and so being aware of your soil’s health and what interventions to make will make all the difference in the quality of your blooms. Bare, compacted soil dries out quickly and supports weaker growth.

August is a fantastic time to improve beds by adding a homemade garden compost, leaf mould, or well-rotted manure to improve drainage, moisture retention, and that all-important nutrient availability. Although summer gardens may boast more color and interest than during winter, there are plenty of opportunities to make your winter garden more magical and more desirable for wildlife.

Tidying seed heads away immediately can remove valuable winter interest and food sources for wildlife. Beautiful plants such as rudbeckia, echinacea, teasel, alliums, and ornamental grasses should be excluded from your deadheading activities, because as the year progresses they will provide the most dreamy structure and also supply valuable seeds for birds throughout autumn and winter.

Lavender is one of the most delightful plants in the summer garden; it’s incredibly fragrant, and pollinators adore it, so it’s the perfect plant for attracting bees and butterflies. One of the most common mistakes in August that gardeners make is to cut it back too hard, and whilst regular pruning is sensible to keep your lavender plant healthy and compact, cutting into the old and woody stems can stress the plant and make it harder for it to recover.

The trick is to prune whilst there is still plenty of green growth on the stems, and once flowering has finished in the late summer you can trim back the spent flower stems, and gently shape the plant to create a neat mound that allows light and air to reach the plant. Achieving an immaculately striped lawn can be challenging at the best of times, and never more so than under the summer sun, when lawns quickly turn brown, and growth becomes weaker.

A closely cut lawn may feel like it will be neater, but it is far more vulnerable during dry spells. Scalping grass exposes the soil, increases evaporation, and weakens roots. As part of your summer lawn care, be aware that raising the mower blades slightly during August is a great way to help your lawn cope with drought and recover more quickly, as the grass will be longer.

This month in the garden is one of the most abundant times for seed collection and storing from all your favorite flowers, and failing to collect them means missing an opportunity to grow more plants for free next year. Allow seed heads to mature fully before collecting; it’s essential to leave seed pods on the plant until they are brown and papery.

Store seeds using a seed storage tin somewhere cool and dry. Ideal plants to collect seeds from include cosmos, calendula, poppies, sweet peas, nigella, and foxgloves. It can be incredibly tempting to split overcrowded perennials whenever you notice them, but August is not always the best time to do so, as dividing plants during hot, dry weather puts unnecessary stress on roots.

For most perennials, it’s completely fine to wait until autumn or spring when conditions are cooler and moisture levels are more consistently reliable. August is a month for setting up your garden for success in the year ahead. If you can avoid premature cutting back, steady and consistent watering, and feeding of your plants, maintaining your soil, and supporting stressed plants, you put your garden in the best position for glorious displays of flowers next year.

Proper lawn care is essential during this time.