Ornamental grasses

What are ornamental grasses?

The term ‘ornamental grasses’ does not describe a particular plant group. Rather, it is the designation for all species of grass which are so attractive that they look great next to shrubs, for example, in the garden.

The plants are an optically appealing addition in the garden and much more than just a space filler. Ornamental grasses captivate with their different colours and shapes. So, for example, there are small ornamental grasses. These look best when planted in a group.

Other ornamental grasses are so conspicuous that they make wonderful soloists. They effortlessly draw the attention in the garden. Alternatively, ornamental grasses can be planted as an inconspicuous planting partner. In such situations, they playfully surround bright flowering shrubs, for example and ensure a beautiful overall image in the garden or on the balcony.

Ornamental grasses from the Poaceae family look particularly attractive. These are also referred to as sweet grasses. Plants from families similar to grasses such as sedges, bulrushes and rushes are often counted as ornamental grasses. They are extremely similar to ornamental grasses and are planted in similar ways in the garden.

Ornamental grasses are available as annual and perennial plants. The annuals die after one year. Perennial grasses last significantly longer. They are sometimes also called shrub grasses.

What do ornamental grasses look like?

Ornamental grasses are available in lots of different colours. The colours range from all the shades of green to brown, yellow, grey and silver. The plants change colour throughout the year, depending on the respective time of year. Reed grasses or moor grasses, for example, illuminate even at the end of the year in powerful colours. Carex pendula, woodrush and hard rush are green all year round.

The leaves of ornamental grasses are highly decorative, yet unobtrusive. The plants themselves are also extremely easy to care for. This is what makes ornamental grasses more and more popular when designing gardens and beds.

Some ornamental grasses grow up to four meters tall, others remain smaller, as mentioned above, and only grow to a height of a few centimetres. The various ornamental grasses also grow in different shapes: while some develop in an arching overhang, others have leaves that stand straight upright. In others, the leaves grow with such a flat hang that they almost lie on the floor. Japanese forest grass is just such an example.

Almost all ornamental grasses have long, narrow leaves.

Growth shape, flowers and fruit

Ornamental grasses are divided into clumping grasses and running species. Clumping grasses tend to have more dense growth in bushes. They do not require very much space. Running ornamental grasses in contrast are rampant. They quickly take up large areas in the garden. If you don’t want that, you can hem them in with a self-made bed border.

Almost all ornamental grasses develop flowers at some point. Some plants, such as the giant cane and Buchanan's sedge, have less conspicuous flowers. The flowers of spear grass, mountain red-top and woodrush are more easily recognisable. The panicles on Chinese silver grass and pampas grass are particularly noticeable.

In addition, lots of ornamental grasses also form infructescences. These often only differ from flowers in their colour. The infructescences of Gray’s sedge, needle grasses and Job’s tears grass, for example, are particularly attractive.

If you’re looking for visual protection, you can build a raised bed and plant it with tall ornamental grasses along the very back row, to create a natural and attractive barrier.

The proper location and soil for ornamental grasses

A sunny spot in the garden is well suited for most ornamental grasses. The sun-loving varieties include, among others, sedge, moor grass and Chinese silver grass. Millet grass grows brownish red and turns a yellow colour in the autumn. It has practically overtaken foxtail fountain grass in popularity.

All these grasses need a nutrient and humus rich soil.

Other ornamental grasses do well in shady places. You can plant evergreen sedges here, for example. Woodrush, Japanese forest grass and tussock grass also thrive here. You can also plant the golden-yellow wood millet in a dark corner. It brings liveliness to these places.

The soil for ornamental grasses should be loose and humus-rich.

Ornamental grasses for cold and warm periods

Ornamental grasses can be sub-divided according to their flowering periods. Some grasses tend to flower more in the cool time of year. These are also called cold-season grasses. Others flower when it is warmer. These are warm-season grasses. Gardeners in North America in particular differentiate between ornamental grasses in this way. The climate there is also significantly more extreme that at our latitudes. This has a major influence on the growth of the grasses.

Cold-season grasses often do well in the shade. They are frequently winter or evergreen and also grow well in the cold. They grow shoots early in the year and accordingly flower as early as late spring and at the latest in early summer. These ornamental grasses enter a rest phase in the summer months. The cold-season grasses include, among others, sedges and Japanese forest grass.

Warm-season grasses grow shoots later. They often only flower in late summer. These plants include, among others, Chinese silver grass, switchgrass and foxtail fountain grass. These ornamental grasses wear their foliage as winter protection and are often planted as an addition to shrub beds.

How can ornamental grasses be planted in the garden?

Ornamental grasses are perfect for bed design. The often only stand out at a second glance and are therefore unobtrusive. Garden designers often call ornamental grasses structural plants. The create a beautiful contrast to flowering shrubs, for example.

Ornamental grasses such as pampas grass or switchgrass have magnificent flowers and intensive colours. These ornamental grasses are therefore also good soloists. The pampas grass ‘Pumila’ in particular easily draws amazed looks in a sunny corner in the garden. Finer grasses such as the spear grass or quaking grass are well suited for planting around optically outstanding plants such as shrub sunflowers or dahlias.

Remember when designing your bed that ornamental grasses tend to get going later in the year in a sunny bed. They often only start to grow shoots in late spring. With a little luck, they will have grown so tall in the early summer that they can easily be seen in the bed. It is best to plant them together with shrubs or dwarf trees and bushes. They only flower in mid to late summer. To stop the bed feeling empty or bare in the spring, you can add some early colour with bulb flowers and spring shrubs. Plant the ornamental grasses individually or in groups in the bed, depending on how tall the ornamental grasses grow and how dominant they appear.

Foxtail fountain grass looks beautiful almost all year round. It is a delicate bush with fine stems and leaves from spring to summer. It is light-green to grey. So foxtail fountain grass looks good with larkspur, summer daisies and the tall garden phlox. Many of the plants have already finished flowering by mid-summer. Then the ornamental grass can shine with its inflorescences in the bed. It appears in beautiful pastel colours into the autumn. Combine it with autumn flowers. The foxtail fountain grass turns slightly brown in the winter. Then the fruit spikes remain on the plant.

The sun-loving ornamental grasses, and also the plants which thrive in the shade, can be perfectly combined with plants with which they form a beautiful contrast. Not all flowering plants thrive in shady locations. So you can count on ferns or shrubs with conspicuous leaves for these places. Hostas are a good planting partner in the bed, for example.

Many shade-loving ornamental grasses are evergreen. So you can happily combine them with bulb flowers and spring shrubs. This will bring flowering splendour to the garden as early as April and May.

If you want to know more about when you should do what kind of work in the garden, you can find out the best times for all the important tasks in our Gardening Calendar.  

Planting ornamental grasses

You can now pick up ornamental grasses at almost any nursery or garden centre. Ornamental grasses are generally available from these outlets in pots. If you buy the plants in summer, make sure that the ornamental grasses have already grown nice and bushy. The foliage should be strong and healthy.

If you buy the plants in the spring, the grasses will still be in their winter rest phase. In this case, take a close look at the rootball. The pot should be well rooted but not dense. If this is the case then, in all probability, you will have found a healthy plant.

When back home, plant the decorative grasses in the bed as quickly as possible. The small pot from the nursery will not be enough for long. The plant cannot develop healthily and grow strongly in it. If you slightly moisten the root ball it will be easier to remove from the pot.

Then dig a sufficiently large hole in the bed. It should be about as deep as the previous pot is tall. Place the ornamental grass in carefully and fill up the planting hole with soil. Push it down gently and then give the ornamental grass plenty of water. The water closes the last spaces between the roots and the earth. This will help the roots to grow in well. Water the ornamental grass regularly until it is rooted.

For shade-loving grasses, it is best to cover the soil around the plant with a layer of mulch. It should be about 5 cm to 7 cm thick. The layer retains the moisture in the soil and prevents weeds.

Alternatively, you can also grow ornamental grasses in a sufficiently large plant container; it should be at least twice as large as the root ball. The container should have a drainage hole, cover this with a layer of expanding clay as drainage, followed by container potting soil or loose garden soil.

Caring for ornamental grasses

It is best not to work the ground around decorative grasses with a hoe. You could damage the roots or even the plants themselves. This will set back the growth again and again and the plants will develop poorly. As a result, it will take longer to achieve closed planting in the bed.

Lots of ornamental grasses do very well in dry conditions. So you will not need to water them overly regularly. You can also spare fertilising as a rule. However, tall growing ornamental grasses such as pampas grass or Chinese silver grass do develop better if you give them some organic fertiliser every two years. It is best to do this in the spring. Mature compost or cow dung is most suitable for this.

Some ornamental grasses do not tolerate fertiliser at all. It causes them to grow corpulent and often also lose their leaves. Therefore, you should not fertilise feather grass, quaking grass or blue fescue. Water grasses and shady grasses grow rampant. Rushes are an example of this. They do not need fertiliser either.

You can also cultivate your ornamental grasses in pots. They look just as good in a container on the balcony or terrace. However, you should water these plants regularly as they cannot draw water from the surrounding layers of soil.

You can easily use water from a water butt or fountain to water the plants using a hose and the Bosch GardenPump 18. If you combine the pump with the Fontus cleaning equipment you can create a mobile garden watering device.

Pruning ornamental grasses

Ornamental grasses such as pampas grass or Chinese silver grass are easy to prune. Many of them will only need pruning back to about 10 cm once a year. This is easy with sharp garden shears such as the EasyPrune from Bosch. These are reinforced, so that you can also cut through larger amounts of leaves at once. You can also use a saw for particularly strong ornamental grasses. Pruning is easy and safe with the cordless KEO garden saw from Bosch. After pruning the plants will grow back again quickly. Provide your grasses with plenty of water. If you want to use water from your water butt, a garden pump such as the GardenPump 18 can help to easily transfer the water from the butt. You can combine this pump with the Fontus mobile cleaning device for watering.

You must wear gloves when pruning. The leaf margins of ornamental grasses can be extremely sharp.

Evergreen ornamental grasses do not require pruning. Simply collect the dead leaves from the plants in the spring. Gloves are also important here so that you do not injure yourself on the sharp-edged leaves.
 

Propagating ornamental grasses

You can separate ornamental grasses for propagation. This is best done in the spring, before the plants grow new shoots. Do this by cutting off a part of the root area with a sharp spade. Plant this section in a different location in the garden.

If you want to propagate the plant, division is the proper way to do it. However, division is not important for the plant’s health. So you do not have to divide the plant.

You can also sow ornamental grass seeds. However, this takes a long time and is somewhat difficult with some plant breeds: the offspring from these plants are generally not pure variety offsets of the mother plant.