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Growing ornamental grasses – the beginner’s guide
Last Updated on January 21, 2020 by John
Ornamental grasses have grown in popularity over the last few years not just because they are very low maintenance but because they grow well in less than ideal soil conditions. Moreover, they are resistant to most pests and diseases which is a huge bonus, they grow quickly to fill a given space, and lots of types offer something of visual interest the entire year.
There is truly a form of ornamental grass for any type of garden or garden theme. You can find evergreen or deciduous varieties of ornamental grass ranging in height to fit all of your needs be it 30cm tall ornamental grass for the edges or borders and pots or grasses that reach up to four metres which make a great focal point. You can combine different ornamental grasses as your specimen plants, for your container displays, or be part of an otherwise busy garden border collection. Primarily known for the foliage they provide, ornamental grasses also offer rather spectacular flowers.
Where to grow ornamental grasses
Given that there are so many types of ornamental grasses from which to choose you can truly find a variety for any position in your garden. If you have a spot in your garden that is usually warm and dry you can grow the Festuca variety. If you have an area that’s heavily shaded perhaps under another tree with soil that is very water retention, you can pick a variety of Acorus or Milium but do check the variety you choose is suitable for your location. If you live near the coast and you need to grow something that’s tolerant of sea air, pick Cortaderia famous for it’s large white or pink flowers. If you have a pond and are looking for a marginal grass, you could try Juncus. It is important to note that taller grasses need a place that is somewhat sheltered so that the taller flower spikes don’t get damaged by heavy wind although Cortaderia is a very wind-resistant variety.
Growing ornamental grasses in containers
You can, of course, choose to grow your ornamental grasses in containers which gives you the opportunity to cultivate any variety you so choose which simple modifications to the placement in your garden. This is also ideal for people who don’t necessarily have an area where they can plant in the ground but instead have a raised porch or terrace upon which they wish ornamental grasses be displayed in all there glory.
When you grow your ornamental grasses in a container to simply want to be cognizant of the size of the container as it relates to the root system of the grass you want to grow. Place the container where you want it to be permanent rather than planting and then trying to move now heavy container somewhere else in your garden. Be cognizant of the location you choose as it relates to the type of grass you are growing and the amount of sun exposure and wind exposure. A soil-based compost is usually ideal, something like a John Innes No2.
Planting ornamental grasses
You can plant ornamental grasses at any time throughout the year but it is recommended that you do it in the spring or the autumn if you have the opportunity. If you are growing a grass that prefers dry soil you can help keep the drainage at optimum levels by adding horticultural grit into the soil and mixing in well before you plant.
When you are ready, dig a hole and put the plants in the hole so that it reaches the same depth that it was in its original pot, never plant them deeper as this can cause the plants to rot off. Back still the hole and firmly packed down the soil so that you will alleviate any air bubbles. Once it has been planted you want to water it well to help the soil settle.
Most grasses are very low maintenance once established will thrive without any care, however for the first 12 months check to see if they need watering especially if planting during dryer conditions.
Pruning and general care
Ornamental grasses are very low maintenance, as mentioned and they do not require regular feeding. Otherwise, in terms of general care, you can refer to the variety you have selected for any watering requirements but even this is minimal once they are established with the exception of grasses grown in pots that should be checked regularly.
For the pruning, if you have tall ornamental grass or you see that the long flower stems have become messy or broken, you can cut them back at any time of year to keep them looking tidy. Again, ornamental grasses have next to no issues with diseases or pests so you won’t have to worry.
You can leave your ornamental grasses uncut throughout the winter. If you have a deciduous variety you should cut it back at the beginning of March as the foliage with help protect the root system over winter. If you have an evergreen variety do not cut it back until April through July. The evergreen grasses don’t really need to be cut back all too heavily and can benefit more from a simple light trim to keep them looking there best. You can tidy up your evergreens by pulling out the older stems. Some of these grasses are sharp so if you are going to comb through them and pull out the older stems wear gloves. It’s usually better to use a good pair of secateurs or scissors to avoid damaging the plant.
Propagating ornamental grasses
One of the best ways to propagate grasses is by dividing established grasses you already have. You can divide your ornamental grasses at the beginning of spring. If you have a very mature clump of ornamental grass they can be somewhat difficult to lift it out of the ground. In order to divide and propagate larger clumps, you will need to dig the plant out of the ground and then use large garden spade placed directly into the crown of the plant, situated back-to-back. From there you can pull the two handles down to separate the clump and then replant both where you so choose. Sometimes you can get away with lift a large clump and then simply just slicing into small pieces with a single spade too.
Lift seedling from grasses that have self-seeded
If you have grasses that self-seed, such as the Stipa tenuissima pony tails, simply keep your eyes peeled for the seedlings and when you find them, simply carefully lift and pot on some of them into small pots and grow on in a sheltered spot until established.
There are hundreds of varieties of grasses but one of our favourites includes Miscanthus flamingo is a deciduous grass that reaches 1-2m in height and spread with pink flower blooms at the end of summer which turns silver. They prefer full sun in moist but well-drained soil but will thrive in sheltered or exposed positions.
Acorus variegatus is a popular variegated evergreen grass that reaches heights of only 25cm and thrives best in full sun or partial shade making it perfect for container growing. If you have a pond it also grows well as a marginal pond plant in shallow water. This also makes it perfect for planting in wet or moist soils where many kinds of grass will not grow.
Another slightly larger grass that reaches a height of 50 to 100cm is the Briza Golden Bee variety. This offers stunning flowers in the summer and is a golden semi-evergreen grass. It’s easy to grow in moist fertile but well-drained soil but needs full sun, however, it will thrive in both sheltered or exposed sites
Calamagrostis Karl Foerster is a deciduous green grass that offers bronze flower flowers that later fade to brown standing upright reaching an impressive height of around 5ft making it one of the largest types. Its grows well in most soils except the very poorest and will thrive in full sun or partial shade in sheltered or exposed sites.
Stipa tenuissima also is known as Mexican feather grass is a popular grass that has fine delicate foliage and feathery flowering panicles flowers which will move very well in the wind without getting knocked over. Its grows well in moist but well-drained soil but needs full sun to thrive in sheltered or exposed sites.
Pennisetum villosum also is known as Feathertop is a deciduous grass that is one of the quintessential ornamental grasses with it’s bunny tail-like flowers that are soft and fluffy. It only grows to around 30-50cm and needs a sheltered position in well-drained soil.