With the rain showing no sign of abating, Hannah Stephenson asks an expert how we can protect our plants from the worst of the weather

WHILE the incessant rain may have left gardeners’ water butts overflowing, it has also inevitably claimed its share of casualties.

Waterlogged plants, nutrients leached from the soil and pest and disease problems can all result from consistently wet conditions, and those gardeners with poor drainage systems are likely to be the hardest hit.

When soil is waterlogged, plants literally drown. Water fills all the air spaces between the soil particles and this prevents oxygen from reaching the roots. In turn, this causes the soil to stagnate and prevents root growth.

If plants look a bit sickly after a week or two of solid rain the minerals may have been washed away. Restore the vigour of plants by giving them a dose of liquid seaweed fertiliser.

“It’s absolutely vital that one doesn’t walk on the soil when it’s this wet because you compact it and destroy its structure. Don’t dig it or disturb it but leave it to its own devices until the tide goes out,” says Guy Barter, head of RHS advisory service.

Plants likely to be worst affected include those from dry climates such as lavender and rosemary, while lawns can also suffer as a result of excessively wet weather, he notes. Don’t mow the lawn in wet weather or even walk on it, as the pressure can cause structural damage, especially to those grown from seed in spring – most established lawns can cope with excessive rainfall.

Barter advises gardeners to shelter pots of lavender and other container plants by a wall, or even put waterlogged pots on their side for a few days to allow them to drain a little. You may need to repot them in the spring, as the compost may be spent.

But the wet weather isn’t all doom and gloom for gardeners.

“Paradoxically, lawns will be growing in these temperatures,”

points out Barter.

“While in the vegetable garden vegetables will still be growing, so leeks will thrive and cabbages will still be swelling slowly through this weather. By April many things will have come good.”

Bulbs shouldn’t be affected by the continuous rainfall either, he says.

“They are really good at surviving this sort of thing. Snowdrops and daffodils in particular are excellent at adapting.

Bulbs are generally very tolerant of wet soil.

“We might even get a better show of bulbs because in conditions like this they will be photosynthesising in the increased light as the year progresses.”

Herbaceous perennials renew a large part of their root system annually, so they can recover from soggy conditions.

Perennials also have shallow root systems so they can flourish in situations with a high water table.

Most, including those such as hardy geraniums and autumn- flowering asters, that do not normally live in wet environments can cope well with wet conditions.

Plants with big, lush green leaves thrive in really wet weather. Rodgersias, rheum (ornamental rhubarb) and hostas are well-known moisture lovers. Conversely, avoid anything with small, leathery or grey leaves.

Alpines, particularly the succulent ones or those with hairy leaves such as sedums and some sempervivums (houseleeks), are vulnerable to wet weather, so if you haven’t yet covered them with cloches, do so before it’s too late.

Don’t plant bare-root shrubs such as roses until the soil has dried out a little, Barter advises.

“Gardeners will have rose bushes and trees and fruit bushes and turf ready to go out and they must keep that protected because it will be a rush trying to get everything planted when the soil finally dries up in February, March or even April.

“Gardeners need to keep their new plants in good condition ready for the happy day when they can put them out,” he says.

Anyone who has bought a bare-root plant should make sure the roots don’t dry out in the meantime, he urges.

“Take it out of the packaging and pot it up or wrap it in wet newspaper or straw, put a plastic bag over the roots and leave it in a shed ready to go out in its final position later on.”

While fruit trees love the moisture, the relatively warm weather may lead to earlier blossom, not a good thing in our climate because of the late frosts we so often suffer.

Gardeners who want to avoid too many casualties in future years may consider building raised beds, improving soil drainage and planting species which are happy in wet weather.

It may be worth thinking about creating a bog garden too, which has the added bonus of attracting wildlife – plant irises, carex, gunnera, primulas, hostas, rheum and rodgersia.

Of course, pests come into their own in wet weather and the number one culprit is the snail.

“A wet, mild winter is slug heaven,” says Barter, “so they will be in poll position to start breeding come April. At the moment it’s too cold for them, but you often find bulb flowers being damaged by slugs and snails. I find putting down an old cabbage leaf (held down by a stone) next to plants which are being attacked works well as a trap. Slug pellets don’t normally work at this time of year because the slugs aren’t moving enough to find them.”

Some diseases such as leaf spots persist on plants which are in leaf during wet weather. If you find outbreaks, prune out infected material.

Lastly, as the rain will have washed many of the nutrients out of the soil, give it a pick-me-up with a fertiliser rich in potassium, such as sulphate of potash or rose fertiliser, and your plants should come through the torrent of rain with few problems.