Ornamental Grasses: Movement, Height, and the Autumn Arrangement

Grasses are the material that turns a competent autumn arrangement into a good one, and they are almost never ordered because nobody knows what to call them. "The wispy bits" is what we usually get, and it covers about eleven different things.

What they actually do

Flowers are static. A rose in a vase on Tuesday is in exactly the same position on Thursday. Grasses move — in a draught, when someone walks past, when a door opens — and that movement is the single thing that separates an arrangement that looks alive from one that looks arranged.

They also provide height and transparency simultaneously. You can add eighteen inches to an arrangement with a grass without adding any visual weight at all, because you see through it. Nothing else in the bucket does that except very fine branching material.

And they are cheap. Grasses are the least expensive thing on most wholesale lists, and in autumn a great deal of it can be cut from a garden or a roadside verge for nothing.

The useful ones

• Panicum (switchgrass) — the finest and airiest, a cloud of tiny seed heads on thread stems. 'Frosted Explosion' is the one to ask for by name and it is the single most useful grass in floristry.
• Pennisetum (fountain grass) — soft bottlebrush plumes, purple-bronze or cream. Substantial enough to read as a flower in its own right.
• Lagurus (bunny tail) — small, round, unbelievably soft cream tufts. Charming, easy to overuse, and the grass most likely to end up in a dried arrangement in a teenager's bedroom.
• Miscanthus — big silver-pink feather plumes in autumn. Real scale; excellent for large installations.
• Setaria (foxtail millet) — arching green or bronze caterpillar-like heads. Superb movement, and the arch is a shape nothing else provides.
• Briza (quaking grass) — tiny flattened lockets that tremble constantly. Delicate and quietly wonderful.
• Wheat, barley and oats — the harvest register. Barley in particular has long awns that catch light beautifully.
• Bunny tail's larger relative, pampas — see below.

The pampas problem

Pampas grass had a decade in the sun and is now the most divisive material in floristry. Two honest points.

First, it sheds. Aggressively and permanently. A dried pampas plume in a heated house drops fine fluff continuously for as long as it exists, and it gets into everything. A light coat of unscented hairspray or matte fixative slows it considerably and is standard trade practice — do this outdoors.

Second, it is genuinely invasive in parts of North America, and its ubiquity in event work has produced a real aesthetic fatigue. It is not a bad plant, but it is no longer a neutral choice, and using it now reads as a specific stylistic decision rather than a default.

If you want the scale without the associations, miscanthus plumes do nearly the same job and shed far less.

Fresh versus dried

Grasses can be used either way, and the difference is worth understanding.

Fresh, cut green and still supple, they have movement and a soft green colour, and they will dry in the vase over a fortnight — usually shrinking and shattering somewhat as they go. Fine for a short arrangement, messy for a long one.

Dried properly — cut at the right stage, hung upside down in a dark dry airy place for two weeks — they hold indefinitely. The right stage is just as the seed head emerges and before it fully ripens. Cut too late and the head shatters and drops seed all over the floor for months. This is the single most common error with grasses and it is entirely a timing question.

Dried grasses are also the easiest thing in the world to over-bleach and over-dye. The natural range — green, oat, wheat, bronze, silver, dusty pink — is better than anything achievable with a dye bath.

How to use them

Above the flowers, not among them. Grasses belong emerging from the top and sides of an arrangement, above the mass, where they are silhouetted against the wall behind. Buried in the middle they do nothing.

Three to seven stems is usually right in a domestic arrangement. Grasses are a seasoning, and an arrangement that is one-third grass reads as unfinished rather than as light.

They pair naturally with everything in the autumn register — dahlias, chrysanthemum, berries, pods, amaranth, rudbeckia — and surprisingly well with very formal material. A tight arrangement of white roses with panicum floating above it is far more interesting than the roses alone.

Our Wildflower Garden Bouquet carries grasses through the late season, and Moody and Dramatic Dark Florals uses them for silhouette against dark material. For an arrangement built deliberately around movement and height rather than flower count, ask through the Designer Flower Mix.

Cutting your own

Autumn in the DMV is full of free grass. Roadside verges, field edges, your own garden. Two cautions: get permission on private land and do not cut in parks or on National Park Service ground, where it is not permitted; and check what you are cutting, because a few common roadside grasses are aggressive invasives whose seed you do not want to distribute by carrying a ripe head through three neighbourhoods.

Cut long, cut before the head ripens, hang it in a dark wardrobe for a fortnight, and you have a year's worth of the most expensive-looking material in floristry for the cost of an afternoon.