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Clay soil has a reputation for being hard and unsuitable for plants, but that is simply not true. Clay soils work quite well in gardens and in fact, bring rich nutrients to your plants. So whether you have clay soil, or think you do, rest assured that there are ways you can fix it, break it up, or grow perfectly stunning shrubs, trees, and plants that do well in such conditions.
What is it?
For starters, clay soil is a soil structure made with fine particles all of which are close together. That compaction prevents air and water from easily moving through which makes drainage a problem. In fact, waterlogging is common and for many plants, this can rot the roots. It also makes the soil physically heavy, so weaker, softer plants cannot cope. Being heavy, it is also a laborious challenge to dig up and takes a lot longer to warm up when Spring hits.
You can use a simple soil test kit to determine whether you have clay soil, and from there decide:
- To amend the soil
- To find plants suitable for the soil
Amending clay soil to improve what you can grow
If you have confirmed you have clay soil you can make improvements with time. The biggest issue is that of poor drainage. You want to avoid standing water. To do this, you need strength and time. Start by digging the soil up very deeply and adding bulky pieces of organic matter throughout. Coarse grit, well-rotted wood chips, leaf mould, all work well to break it up. Don’t go straight for an abundance of wood chips because they are the biggest and bulkiest; the bacteria required to break them down depletes the soil of much-needed nitrogen.
It is best to start in manageable sections and not to try and change the entire garden at once, especially if you have a big garden.
Using Liming agents, like calcium and Lime
What about acidic, clay soil? Sometimes the soil is heavily acidic, which means you can amend it with liming agents. Liming agents, like calcium, forces the particles to clump together instead of packing together and this improves drainage. You will want to use a soil pH kit to test the acidity before you try this method, just to make sure the soil is suitable. You should follow the instructions per packet.
Gypsum is another option, one that changes the structure without changing the acidity. With these, you should test small areas before you apply to the entire garden.
What if my plants are already growing? That’s ok. If your plants are already established, you can still improve clay soil by adding thick layers of leaf mould and compost over the summer to the surface of the soil. This will improve moisture retention and prevent it from cracking. With this, don’t worry about digging in the mulch as the worms or insects will move nutrients down into the soil for you.
- Keep away from the soil when it is wet. If you walk or stand on it, you will only increase the compaction.
- Similarly, do not dig or plant when the soil is wet.
- If you can, lay down wooden plants on which to walk so that your weight is evenly spread as you work throughout the garden.
- Dig over the Autumn when you want to add organic matter.
- Create ridges on the surface, with a rake across the top for example, so that frost in winter can get in and forcibly break apart the clumped soil.
Best Plants to Grow in Clay Soil
Rest assured there are ample plants you can grow well in clay soil, so long as you have the right levels of sunlight.
If you want trees, there are native British trees like the Elder, Ash, and Oak which will do well in clay soil. Birch and eucalyptus are ideal if you are growing tall trees for perimeters or borders. If you prefer fruit trees, apples and pears can be useful. Conifers work too if you invest in juniper, pine, or thuja.
Shrubs work well in clary and tend to do better with wet conditions once they get established. There are shrubs with berries and evergreen leaves like cotoneaster, pyracantha, or mahonia.
Then there are flowering shrubs like buddleia, forsythia, and weigela. Some roses do well too if you give them a lot of organic matter and have a spot in the sun.
Flowering plants work well if they are perennials. Once they establish themselves in the soil, they can give you beautiful floral displays.
- If you have a shady area, fill it with hostas or euonymus. If you want cover, try vinca or alchemilla mollis.
- If you want flowering perennials, the daisy family has asters and coreopsis.
- Woodland plants do well like phlox, aconites, and Japanese anemone.
- If you need bedding plants for sunny areas, geraniums, cranesbill, and pulmonaria are ideal.
- If you have an area with full sun to partial shade, astrantia or solidago are well suited.
- Don’t let the climbers go unnoticed though. You can grow honeysuckle, clematis, or ivy.
- If you prefer bulbs, you can grow snowdrops or narcissi in clay.
Plants work well too, particularly the hardy plants that tolerate full sun all the way to partial shade. These include ferns, Japanese anemones, Hosta, Ajuga, and Ivy. Other plants like hydrangeas or viburnum tolerate partial shade.
You can grow vegetables in clay soil too, particularly classic crops that are harvested in the late summer or Autumn like squash, pumpkin, onions, cabbage, cauliflower, or leeks. Remember though, that while these are tolerant of clay soil, they need ample sunlight.
Top 10 Plants for Clay Soil
- Alchemilla mollis is a great plant for edging. It will give you wispy stems that are frothy from a distance. The colours are yellowish-green flowers that grow very low to the ground and can tolerate partial shade.
- Crab apples are beautiful in spring, with their rich colours, white blossoms, and colourful fruit. These are best for larger spaces with good sunlight.
- Bergenia cordifolia is known for their spires of red or pink flowers and their evergreen leaves so beautiful and large they have earned the nickname “elephants ears”. They are suitable for ground cover and tolerant of shade.
- Spiraea japonica is a shrub with lots of tiny flowers that are grouped in small clusters. It grows well in clay, is tolerant of drought, and will attract bees and butterflies to the yard.
- Viburnum tinus has white flowers that open at the end of winter and give your garden a delightful backdrop in preparation for springtime. The growth is dense, compact, and very useful for creating an enclosure.
- Syringa vulgaris or lilacs are tough but glorious. They flower for a short amount of time but during that time you can cut the blooms for displays, and enjoy their rich scent.
- Rose ‘Roald Dahl’ can be found in a repeat flowering variety which means you can enjoy 2 flushes minimum each year. This tolerates clay soil well and has a very rich scent.
- Ribes sanguineum is a flowering currant plant that is vigorous and grows quickly. This shrub will establish itself well and reach up to 2 metres. If it gets too big, feel free to prune after flowering once summer arrives.
- Honeysuckle is a scented climber that quickly perfumes an area and is easy to grow up and over any doorway, pergola, or seating area.
- Pulmonaria is tolerant of shade and is a low growing perennial sure to attract lots of bees to your garden. There are lovely blue flowers that do well when grown next to yellow daffodils.
When to plant
Aim to plant new things in Spring rather than Autumn, so that your plants can establish themselves in dry, warm weather. With woody varieties like trees though, aim for the beginning of Autumn.
Last update on 2021-03-31 / Affiliate links / Images from Amazon Product Advertising API