When it's a rush or a sedge! But how do you spot the difference? Grasses, from the family Poaceae , are one of the most successful plant groups on earth.
They range from diminutive, fine-leaved fescues Festuca , only a few centimetres high, to mighty bamboos many metres tall.
Mankind depends on grasses : wheat, barley, rice, oats and sweetcorn are all grasses. But not every plant with narrow, strap-like leaves is a member of the grass family. Most grasses prefer well-drained, dryish conditions and full sun, whereas most sedges, rushes and reeds like it moist.
Some sedges and woodrushes will also thrive in fairly deep shade. So, as narrow leaves are not a characteristic specific to grasses, other features such as the structure of flowers, stems, leaves and seedheads should be examined.
However, all share the characteristic that their narrow leaves grow from their bases rather than their tips — enabling them to keep growing, even if browsed by herbivores.
Grasses have hollow stems called culms, plugged at intervals by solid nodes bearing the leaves. The lower part of each leaf wraps around the stem, and the upper part forms the leaf blade.
Bamboos are large grasses that have evolved the ability to form perennial woody stems or culms. Grasses first appeared million years ago. Grass flowers are characteristically arranged in spikelets, each made up of one or more florets which are grouped into panicles or spikes.
These usually contain both male and female flowers. More ancient than grasses appearing more than million years ago , and more tolerant of wet conditions. There are some 5, species of sedge. Their stems are solid, not hollow, and usually triangular in cross section. Leaves are arranged spirally in three ranks — grasses have alternate leaves forming two ranks.
Sedge flowers are wind-pollinated, small, often brown or black with separate male and female flowers being borne on the same plants. Juncus are wetland specialists. Their flowers are made up of five whorls of flower parts: three sepals, three petals, stamens in two whorls, and a stigma with three lobes.
The stems are round in cross section, and in many species the leaves are reduced to sheaths around the base of the stem. The bract around the flower can look like a continuation of the stem, so flowers appear to stick out of the side of stems. One that takes almost everyone by surprise is the pink muhly grass Muhlenbergia capillaris , with airy panicles that create a rich, pink haze. For those looking to add to their gardens, the majority of ornamental grasses thrive in full sun and can handle drought magnificently.
Wet summers are a different story, though, where staking is a requisite. Because of their beautiful flowering structures, ornamental grasses are by far the most popular for gardeners, though sedges hold a special place in the hearts of those who prefer shade gardening. Most sedges tolerate shade better than grasses and—depending on the species—they handle a wide range of soils from wet to dry. Carex pensylvanica, sometimes referred to as Pennsylvania or oak sedge, is an ideal lawn substitute or ground cover for a shady spot.
It has a fine texture and a graceful fountain habit that spills over the ground. In our case, we had a bare, shady slope on the edge of the garden that was a breeding ground for weeds and washouts after every rainstorm. Two years ago we decided to cover the bank with small plugs of Carex, and it has since begun filling in nicely to provide a remedy to our problems.
Try to keep in mind that while sedges generally handle shade better than grasses, there are always exceptions to these generalizations; there is a whole host of sedges that thrive in full sun. When choosing a grass or sedge, educate yourself on its size and shape before you incorporate it into your garden. Decide whether you are growing it just for the foliage or for the flower, as well.
Small sedges and grasses make wonderful edging for a border, while larger grasses are fantastic focal points that make strong statements. Sedges are also found worldwide, but they prefer colder, wetter regions than grasses. Rushes also thrive in colder, wetter regions and are typically found in northern regions.
You can determine whether a plant is sedge, grass or rush by looking at the stems because each has a very different appearance. If the stem is hollow it is likely a grass, as there are few grasses that have solid stems.
If the stem is solid, peel the leaves back if the plant has leaves, and roll the stem between your fingers. The leaves on grasses are usually arranged in two rows on the sides of the stems. Sedge leaves typically lie along the stem in three vertical planes.
The leaves of rushes are usually found at the base of the stem and arranged in a spiral. However, the arrangement of rush leaves varies among different species.
The leaf sheath of grasses, which is the part of the leaf that enfolds the stem, are typically open.
0コメント