Grasses are a conundrum. If you plant too many, you end up with a hayfield – not a great look in a garden. They are relatively inexpensive, very difficult to kill and add a lovely soft movement but also take most of the summer to come to maturity. Lazy landscapers shove them in holus-bolus because they will survive just about anything.
A handsome grass placed with some skill will enhance the tiniest of gardens. In containers, just about any grass will give pleasure most of the year. All grasses need to be cut back in the spring. There are two kinds: cool-season grasses that need to be cut back in late winter because they start to grow as soon as temperatures go above zero; and warm-season grasses that can be left for several more weeks, but will look dead so don't give up on them. Just check out which type of grass you've bought, and you'll know how to look after it. Apart from this initial whacking back, there's not much else you have to do.
I like to see grasses anchoring a border (one large specimen such as Pennisetum "Red Head" is a current favourite). It's a matter of finding appropriate perennials and shrubs to grow with it: Put some of the wonderful prairie plants that do so well and you get an exciting, supple mix.
For instance, combine the pennisetum mentioned above with any colour of the coneflower (Echinacea "PowWow Wild Berry") and gayfeather (Liatris spicata "Floristan Purple") to make a blissful late-summer autumn look that goes on for weeks. And it's just as the feathers (or blooms) of the grass come into their showiest best. A spectacular moment in the garden.
Having other see-through plants combined with grasses looks delicate especially if they are near evergreens. Consider Sanguisorba menziesii with its summer bloom of magenta bottlebrush spikes. They herald the frothiness of the grasses to come in early autumn. There are so many good veronicas from white to deep blue to purple that any one in a really sunny spot will work well.
Light is a factor with grasses. Most of them need lots of it and tend to be straggly, seldom standing up with pride if they are in too much shade. But there is one beauty, new this year, which I can highly recommend that will also grow in semi-shade. It's Hakonechloa macra SunFlare, a Japanese forest grass which came through a winter of unpredictable weather, planted in clay and under water for a month in my garden. With very little sun up they popped looking fresh and exciting with elegant gold stems flushed with a dash of orange in the centre and burgundy tips – really gorgeous.
I like most Haks because they make dramatic mounds if left alone, are excellent edgers and great container plants. But if you are going to leave them in place, make sure you allow enough room for the root system to grow fairly large. They are total hell to divide after a few years because of the dense wiry roots. Move them around the first few years and then let them be glorious.
Use grasses with discretion. Do lots of research to find the real size and then add more space for them if you have rich organic soil conditions. Water them when young, not so much in maturity.
You will have plants that will stay in good fettle for decades.
For more plant info, visit marjorieharris.com.