Summer work in the Mixed Borders

Weeding, staking and pest control keep the borders looking their best

With memories of winter feeling ever-more distant, and a heatwave upon us, it really feels as if summer has arrived in style. Standing at the top of Wisley’s iconic Mixed Borders, their presence at 128 metres long and 6 metres deep is truly a sight to behold. The last of the half-hardy plants and annuals grown from seed were planted some five weeks ago, and now their impact is quite vivid. The borders are now full of colour and inspiration.

It is quite a privilege to be able to observe Wisley’s borders through the seasons, but with this comes the responsibility to ensure that they are looking and performing their best at all times, and in the summer months this is achieved by a constant process of monitoring and maintaining. I am lucky to have a great irrigation system to look after my watering requirements, but below are just some of the other activities that fill my days.


Bindweed growing through herbaceous perennials

Annual weeds become less of a problem through the summer months, and much of this can be attributed to the fact that the borders are planted so densely – not only providing us with a mass of colour and structure, but also a strong canopy to outcompete many of those persistent weeds we faced earlier in the season. However, this system of dense planting does nothing to control the presence of bindweed (Calystegia sepium).

Over the winter months, we dig through the beds with a fork and remove then burn any of the rhizome from the bindweed which we find. Plants that have the bindweed rhizome in their root system are lifted out of the ground so that it can be removed. This system does not result in 100% eradication but it does dramatically reduce the quantity of bindweed appearing in the borders through the summer months.

I have a highly organic approach to gardening, so I refrain from the use of herbicides as much as possible. With this in mind, summer control of bindweed in the borders is simply unwinding the stems from their host plant and removing from as low a point as is possible. This can be time consuming, but for me it is the much-preferred method.


The staking of Wisley’s borders is completed in early spring time, before the perennial plants begin to emerge. We use a mixture of green link staking and birch sticks, which are pushed in to the ground to a sturdy depth around the plants.

The birch sticks blend in brilliantly among the plants in the summer months. By using a natural product we achieve a staking system that is camouflaged in its environment, ensuring that the plants still take their rightful centre stage in the beds.

Unfortunately, this system is not foolproof and we still experience some unwanted collapses throughout summer. The heavy rainfall this June and July has certainly not helped and I have been busy ‘emergency staking’ various plants (particularly delphiniums). For plants such as the delphiniums I simply add to the initial grid of birch sticks by inserting additions where possible, before delicately propping the plants back up.

Other plant groups such as large clumps of heleniums require a more sturdy approach, so for these situations I drive a perimeter of garden canes around the plants before tying strong garden twine around the canes to support the plants.

Pests and diseases

Agapanthus gall midge in the borders at Wisley

The borders have not suffered too badly from pests and diseases this year, but one pest whose devastating presence is abundantly clear is the agapanthus gall midge. The larvae of this small fly causes flower buds not to open, and to turn brown and quite unsightly. It’s a great shame, but all I can do is to remove infected flowers from the stem and focus on all the other plants that are performing right at their best.


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