Water-wise Gardening
Advice on water-wise gardening often recommends planting drought-tolerant varieties, however, most drought-tolerant plants don't like wet ground and here in this part of north Bristol our soil is a clayey loam with impeded drainage that can get waterlogged in places. This blog is, therefore, going to focus on water-wise gardening when you have a clayey soil.
There is an old gardeners' saying that goes "it never rains in pots", which refers to the fact that you have to water plants in pots even if it has rained (in spring and summer). Raised beds don't need as much watering as pots but they do need more watering than traditional flower beds. To reduce the need for watering, plant in the ground whenever you can. Raised beds can be useful if you want to grow plants that need good drainage and this can include drought-tolerant plants. If you do use pots, make sure you place a saucer or tray under them in spring/summer to save water and that you remove it in autumn/winter. Moving pots into the shade during a heatwave can also help.
Our next tip is to plant hardy varieties out in late autumn. They won't need watering-in at this time of year, or just once if it is unusually dry. They will also have months to establish their roots before spring hits, making them much more resilient to droughts in spring and summer. These plants will also require less staking and in some cases (e.g. honesty) they will be larger than their spring-planted counterparts. Slugs and snails are less active in the cold winter months so planting in late autumn also allows the plants to toughen up and establish before the weather gets warm and wet in March / April and the slugs/snails are rampant. We have around 75 varieties available to plant in the autumn and winter months.
Applying a mulch of home compost (or leaf mould, soil improver, compostable bark chippings or similar) on top of your soil in autumn and or spring can help keep moisture in. We also recommend placing stones or broken pots on the soil surface to shade the roots of plants such as clematis that are sensitive to drying out.
If we have a drought in spring or summer (with or without a heatwave), you will inevitably need to water your garden but you can save water but doing so wisely. Water early in the morning before the sun is high in the sky, water heavily once or twice a week rather than a little bit every day and water the base of each plant. The same principles apply to newly planted varieties that you didn't manage to get them into the ground in autumn. Lawns don't need watering and will bounce back when the rain returns.
You can save tap water by collecting rain water, which is best done using a water butt. Bristol Water sometimes give away free water butts or sell them at cost with no delivery charge. At the moment (summer 2024), they are giving them away to customers who switch to a water meter. You can also buy kits to convert any large container into a water butt. Make sure your butt has a lid (an opaque plastic or rubber sheet works well) to keep the local wildlife (and cats) safe and to keep the water clean.
If you can't collect rain water, or don't have enough, you can also use grey water. This is tap water that has been used for washing. To do this, you need to use environmentally-friendly soaps and detergents. The easiest way of using grey water is to wash up using a bowl and an environmentally-friendly brand of washing up liquid, then tip the used water onto your flowerbed. As above, aim to water the base of your plant(s).
Finally, there are some drought tolerant plants that will thrive in our clayey soil. Concerns over waterlogging mainly apply over winter so you can plant drought tolerant annuals such as Cosmos in late spring. There are also a small number of plants that can handle both waterlogging in winter and droughts in summer, for example day lillies. Generally speaking, larger plants are more drought tolerant (trees handle droughts better that shrubs that, in turn, cope better than bedding plants) so trees and shrubs that are well suited to clay soils are a good choice. There are also herbaceous drought tolerant plants that do well in our local soil or a pot (check the individual plant descriptions to check which) provided you avoid any areas that get waterlogged over winter.