Grasses are a group of plants that are really hard-working in the garden. They are relatively easy to grow, provide shelter for wildlife and birds and add texture, shape and balance to a variety of planting styles.
It’s no wonder then that many of our Grayshaw & Yeo gardeners come across grasses in clients’ gardens on a regular basis. With this in mind the team decided to brush-up on their grass-care skills with the help of Grayshaw & Yeo gardener Susan Bonnet, who has a wide selection of these plants in her own garden.
So what are the key things to consider when gardening with grasses? To begin with, all grasses are essentially deciduous but most can be treated as one of the following five types.
…behave like perrenials in their native habitat, but grow more like annuals in our uk climate due to the cold and wet. All grasses that flower before the end of May are in this category and include lagurus ovatus, hordeum jubatum and greater quaking grass also known as briza maxima. These grasses can all be grown from seed.
Once planted out in the garden they will vigorously self seed throughout, so keep on the look out for ‘strays’ around the garden. Cut back and dig out the dead growth each year, treating them like annuals. Look out for self set seedlings in the autumn and spring that can be moved and grown-on to establish new plants. This group of grasses are self-sufficient and require no mulching or feeding.
…are those like muhlenbergia rigens. This group needs cutting back to ground level in Feb/ March. Compost the stems or use them as a natural mulch. If green growth has already appeared then just cut away last year’s dry growth.
…are those like anemanthele lessoniana and carex dipsacea. Each spring, rake your hands through the foliage from bottom to top and this will clear out dead stems. Wear gloves to avoid grass cuts. You can also cut these grasses down by half and they will re-grow, provided you do this between April and July and not in the damp winter months.
…include grasses like briza ‘golden bee’. This group can be treated like evergreens (dead stems raked out in the spring), or like deciduous varieties (cut back hard in the spring).
You might also want to grow grasses in containers…
These plants can easily become pot bound with tight root balls, so every 2-3 years you’ll need to remove them from their pots and cut off one third of the bottom of the root ball. Replant the grass in its pot with fresh compost and keep well-watered once a week.
To ensure the plant has time to flower and set seed, make sure they are planted by the end of March. If you need to move them, then this can be done in the spring or autumn. You can also divide grasses into new clumps to make new plants; this is a good way to refresh grasses that are dead in the middle. Cut them into four and replant each quarter, with the newest growth in the centre of the hole.
Use whatever works for you. Some gardeners find that saws are useful for dividing larger grass rootballs. You can also use secateurs or scissors to cut back dead growth.
Grasses prefer nutrient-poor soil, so there’s no need to feed them, but they do need to be mulched to help the plant retain moisture. Be careful to mulch around the crown of the plant, as mulch on top of this area will rot the plant and kill it.
Grasses that flower before mid-summer should be planted in the autumn to allow them time to establish. This includes varieties such as Deschampsia, Festuca, Helictotrichon and Stipa. Those that flower after mid summer, such as Miscanthus, Panicum, and Pennisetum should be planted in the spring.
For more information on growing grasses see the RHS pages here.