For many of us northern UK gardeners this summer has been disappointing, at least weather-wise. But you may have noticed that it doesn't seem to have affected your flowering plants too much. This is because they respond to day length coupled with night-time temperatures, rather than whether we have hot sunny temperatures during the day. So the cool, damp weather has simply meant they have grown bigger, taller and lusher than usual.

In this blog I'm going to talk about a few of the common problems people have in their gardens in summer, especially a cool, damp one - and how to ensure your plants are healthy and flowering well so that you can still enjoy them whatever the weather for as long as summer lasts!

There are four key areas to think about here if you want to help your flowering plants look their best:

Promoting flowers

Most people remember to dead-head their roses as each individual flower dies away. Cutting the blooms off as they go over spurs the plant on to form fresh flower buds in many of our best-loved summer-flowering plants; such as roses, daylilies, penstemons, catmint, some salvias, osteospermums, and a whole host of other lovely garden plants.

The annual plants in your tubs and hanging baskets also benefit from this treatment. If you also feed your plants every couple of weeks you will really give them the energy to keep on flowering away with gusto!

Keeping pests and diseases at bay

In damp summers plants are unfortunately much more susceptible to pests and diseases. Slugs and snails just love this weather and so are out and about, munching away at all the soft, floppy foliage the wet weather is producing. If you can bear it, the best way to deal with them is to go out in the evening or early morning and sleuth around your favourite plants and vegetables picking them off. How you decide to dispose of them is up to you!

Some people swear by copper bands around pots and planters, which are supposed to deter the slugs and snails from sliding up over the edge of the pot; in my experience this works pretty well so long as none of your foliage droops over the edge of the pot, forming an alternative means of the slugs’ accessing your enticing flowers.

Lots of lush growth on the plants means more food for many other leaf-munching critters. My preference here would be to do what you can to encourage a diversity of plant and animal life in your garden, as there are many natural predators which love to feed on these same pests. Ladybirds are a great example of a beneficial insect as they will scoop up hundreds of greenfly a day.

Another option is to spray with a bug killer, but this is not only time-consuming, and expensive if you have a big garden, but in my opinion ultimately self-defeating as you will often kill off the beneficial insects too. Maybe consider this just on one or two cherished plants if you get a problem infestation - and leave nature to deal with the rest.

Mildews and other fungal diseases also tend to be more common when the weather is damp and warm. These live in the soil and then, as raindrops meet the ground, the back-splash disperses the fungal spores and disease vectors to plants in the vicinity. You can’t stop this happening, but it does help if you stake plants that are tending to droop, so less foliage is in contact with the ground. Ensuring air flow around your garden borders is as good as possible also helps, as still, damp air encourages these mildews even more. So don’t plant too close together and look at things like using picket fencing or trellis rather than solid fencing where you can.

Feed me!

Just like people, plants need an adequate intake of food and drink if they are to thrive. In their case, they need soil which has had some nutrients added to it, and which is open enough in structure that their roots can get to the nutrients and to the moisture. Ideally, nutrients should be in the form of manure or other organic matter dug into the soil around the plant. Many people do this either in autumn or early spring.

During summer it’s also good to get some extra nutrients into your plants’ systems to help them keep growing and flowering well. Foliar feeds – that you spray onto the leaves of the plant, or water in around the base – are particularly popular because the plants absorb the nutrients very quickly. Hence the ads on TV which show plants reviving in about 10 seconds! But you could also use a granular fertiliser scattered around the base of the plant as this will do exactly the same job, it just takes a bit longer.

My advice would be to discontinue this supplementary feeding after the end of August, in case the new soft growth hasn’t hardened up enough before our early frosts begin in October.

“Water, water everywhere but not a drop to drink…”

Surprisingly, even in a wet summer such as many of us are experiencing, some of our plants are still probably not getting enough water. Plants suffering from water deficiency won’t thrive or be really free-flowering.

Plants under trees or right next to the house almost always benefit from extra watering. Take a few moments to identify where your problem plants are, then once a week check if they’re wilting, or if the leaves are turning yellow or brown at the tips – these are sure indications of thirsty plants. Also check the soil - if the soil is dry at the surface that’s absolutely fine – but dig a little hole with your trowel and if it’s still dry 10cm down then there’s a problem. Plants affected like this will need weekly watering til the situation improves if you want to get the best summer show from them. Give each plant a litre or more (depending on size) once a week rather than a sprinkling every day, as this will help the plant put down deeper roots and thus help it build up its own survival system for the future.

If you’re going away on holiday, either get a friend or neighbour in to water your plants, or set up a homemade watering system. Take a look at our blog on holiday watering to find out more. 

I hope you find these tips useful – enjoy your garden!

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