Wednesday, November 19, 2014

Fall Grasses

We've had a long and relatively mild fall here, that is until this week when overnight temps got to the low 20's.  Many trees held onto their leaves for a long time wait for a real cold snap to trigger leaf drop.  The Fothergilla I planted last season finally turned the fluorescent orange that I was hoping for.

As the temperature dropped the leaves of this
 Fothergilla 'Mt. Airy' changed to this intense orange color.
It got me thinking about my plant selection.  I am always looking out for plants with exciting fall foliage, reds, golds and oranges.  It got me to thinking that these are more effective when contrasted with cooler or muted colors like pale yellow, green or tan.

One class of plants to fill that role are the native grasses. Late or warm season grasses that produce flowers and seeds in the fall are particularly effective.  The low angle of the sun late in the year really plays off the seed stalks, bringing them to life.  I usually leave these stalks standing through the winter to get the most out of them.  I'll clean up what remains in the spring.

Another benefit of these grasses is as a food source for birds and as shelter for many insects and overwintering animals.

Here are some of the grasses I have that are showing off nicely this fall.

I have planted inland sea oats (Chasmanthium latifolium), aka, Northern sea oats and several other names, along a sloping area by the house subject to erosion.  This grass produces a dense fiberous root system that holds the soil well.  While its native habitat is in moist shady locations it will also tolerate dry shade.  It sprouts early in the spring and can spread, both by expanding clumps and seeds, to form dense stands.

The broad leaves of Inland Sea Oats has a bamboo-like appearance.
These copper colored seeds will persist into winter.

The plan is for this Pink Muhly to fill in along this fence.
When they open the flowers look like exploding fireworks.
Another grass that I have added to the property is Pink Muhly Grass (Muhlenbergia capillaris).  This species is native to the eastern US and the gulf coast, but you're not likely to find it naturally in the mountain regions where I am.  The reason I put this in was the light-catching effect of the flower plumes.  At first I was concerned that this effect would not be strong because I didn't have a good angle for the backlighting. But that's not a problem.  The photo above was taken at 2 PM and there is penty of light being scattered by the flowers even though the sun is still rather high in the sky.

I've found this plant to be slow to establish here. Some of that has to do with competition from the surronding plants. Clumps of pink muhly will expand, but it is not an aggressive spreader.  Larger masses should be mown or burned back in late winter to clean up the clump.

This clump of little bluestem is easily identified
by the silvery seed tufts along the stem..

These next three species are growing wild around my home.  Little Bluestem (Schizachyrium scoparium) is a common native species around here.  It is well suited to dry sunny sites.  It grows well in poor soils.  In excessively rich soils it puts on too much growth and flops over.  As a warm season grass it grows to 2-3 feet by mid-summer.  In the fall it turns golden and produces fuzzy white seeds along the upper stem.  These catch the light and envelop the stem in a silvery glow.  Some selections of little bluestem take on redder shades in the fall.   Small birds feed on the seeds, so I leave these up all winter.

One of the more distinctive grasses I have is Deer-tongue grass (Dichanthelim clandestinum, formerly Panicum clandestinum).  It has relatively broad leaves compared to other grasses.  It is a cool season grass, producing terminal spikelets in early to mid-summer.  Unlike most other cool season grasses, branching and growth continues through the summer.  The name, deer-tongue grass, refers to the shape of the inch-wide leaves, not to any preference for deer to eat it.

Deer-tongue grass persists well into fall, here as a deeply textured mass.
No longer colored, the seeds of Purpletop still catch the light.

Another common pasture grass here is purpletop (Tridens flavus).  When it first blooms in late summer it has a reddish purple color.  When distributed through a field, these blooms cast a purplish haze over the scene.  As the seeds mature the color is lost and the seed stalk becomes a brownish-gold.  As a pasture grass it is very palitable to livestock.  It is also a larval host to a variety of butterflies.

I have not seen purpletop used in any designed plantings, though it does have some interesting features.  The red colored flowers are best appreciated en masse and at a distance.  What might be useful in a smaller garden is to use the 3-4 foot tall flower stalks as a translucent screen between plantings.  Since the leaf blades are concentrated in the lower half of the plant they would not block a view across a planting.  Purpletop grows well on dryish soils in part to full sunlight.

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