Gardening Dilemmas

Welcome to our new series, where Head Gardener Åsa and Head of Horticulture Steve share their expert advice on tackling your gardening and garden design dilemmas.

'Hi !

Three years ago we had a very large terrace built and pavers laid professionally.

With one deep border of perennials and grasses planted up on the south side and narrower borders of shrubs

on both east and west facing sides we now have a weed and moss problem.The pavers were embedded in sand as per manufacturer's instructions. Apart from hand weeding what can you suggest we do to reduce maintenance whilst being sustainable. We look out onto the terrace from the house as you can see in the photograph.'

-Elizabeth

Looking closely, I don't think you have a moss problem more that the joints have become colonised by weeds. The paving itself appears to be in good condition, but the joints have accumulated enough fine silt and organic matter for a mixture of mosses, grasses and small weeds to establish. That's very common on patios and terraces, particularly those surrounded by planting.

I'd recommend tackling it in three stages:

Give the terrace a thorough renovation

Hand-pull or hoe out the larger weeds.
Scrape out the joints with a patio knife or wire brush.
If you use a pressure washer, do so sparingly and on a low setting, directing the spray along the joints rather than straight down into them. The aim is to remove the accumulated soil without disturbing the bedding beneath the paving.

Refill the joints

From the photograph, many of the joints look quite open. Once they're clean and dry, refill them with a suitable jointing material. This will help stabilise the paving and make it much harder for weeds and moss to re-establish.

Prevent organic matter building up

Because your borders are full of planting, they'll naturally shed leaves, petals and seeds onto the paving. A quick sweep every week or two, particularly during autumn, will stop this debris breaking down into compost within the joints.

A few sustainable tips

Avoid using salt or vinegar. Although they're often recommended online, both can harm surrounding plants and soil life.
A kettle of boiling water is an effective way to deal with the occasional stubborn weed without leaving chemical residues.

The terrace already has a lovely, established feel, and a completely sterile, weed-free finish might actually look a little stark alongside your cottage-style planting. Tiny patches of moss between a few stones aren't necessarily a problem, they can soften the appearance beautifully. It's the grasses and larger weeds that I'd concentrate on removing.

Alternatively, you could choose to embrace the look by introducing low-growing, spreading plants into some of the wider joints to soften the paving and enhance its romantic, cottage-garden character. Plants such as Erigeron karvinskianus (Mexican fleabane) and creeping thymes are excellent choices, adding both flowers and wildlife value while remaining easy to manage.