If you are relatively new to reading my garden/design column (as those of you in Fayette County will be), you should know that you can go back and read previous articles by visiting my website www.thefragrantgarden.com . This week’s article on Grasses, Groundcovers, and Vines for Fall Foliage is fifth (and last) in a series. The earlier “episodes” cover a variety of Native and Non-Native Trees and Shrubs that should color well in our fall gardens.
First we will discuss the Ornamental Grasses. Gulf or Pink Muhly (Muhlenbergia capillaris) is a native perennial grass with shiny, wiry, thread-like, dark green leaves and stems growing in a basal clump to 2’ tall. The fall flowering is very showy with “clouds” of airy, open, loosely branched flowers turning pink to pinkish-red. It finishes the season with tan seed heads that remain attractive throughout winter. Height when flowering can reach as much as 3 feet tall.
Red Switch Grass (Panicum virgatum ‘Shenandoah’) is a deciduous bunch grass with green leaves first tipped with red as they emerge in spring. These leaves darken through the summer and turn burgundy in the fall. It also bears reddish-pink flowers over a long summer season. Final height will be 3-4 feet.
There are two especially notable grasses, both in the Fountain Grass family, that offer dramatic color change over the season. Black Flowering Fountain Grass (Pennisetum alopecuroides ‘Moudry’) is prized for its glossy foliage and large purple-black bottlebrush flowers that are present from late summer through fall. Both leaf and flower are mutable; deep green leaves turn yellow and then fade to beige, and the flowers change from purple to brown late in the season. Height in flower may be as much as 3 ½ feet tall. Purple Fountain Grass (Pennisetum 'Rubrum') is a large (to 5 feet), mounding grass with dark burgundy-red foliage all season, and purple-red flower plumes in fall. The former can seed out and become a bit weedy, but the latter is more mannerly and rarely spreads. Both of these grasses look beautiful in containers.
Only a few groundcovers that do well here in Central Texas offer a change of color in the fall. One that does so is Dwarf Plumbago (Ceratostigma plumbaginoides), whose medium green leaves turn reddish/plum tinged, and finally yellow before dropping completely each winter. It grows to about 12-18” high and 2-3’ wide, and bears medium blue single flowers in late summer and fall.
There are a few other groundcovers that are grown for their colorful leaves. Ajuga (A. reptens and cultivars) has light green, dark green, bronzed, purple, or variegated leaves, depending upon cultivar. Purple-leaf Sage (Salvia officinalis purpurescens) has a lovely grey-green leaf color, with purplish new foliage that slowly turns to green over time. The old standby Purple Heart (Setcreasea pallida) is an intense deep purple in full sun, and a little paler in color in the shade. All do well here, but the Ajuga will require more supplemental water than the others.
There are also a few vines which will change foliage color in fall. The Ornamental Grape Vitis vinifera 'Purpurea' is a woody deciduous climber to 20’ with first green, then purple leaves that turn a fiery red in autumn. Don’t expect the small fruits to be table quality, and be aware you may have trouble with several diseases particular to grapes in our area. Simply growing a single specimen in the home garden should prove successful.
Both the native Virginia Creeper (Parthenocissus quinquefolia) and Boston Ivy (Parthenocissus tricuspidata) are clinging vines that are reputed to color well here in fall. Virginia Creeper has 5-lobed leaves that are said to turn brilliant red and purple in autumn. I have one growing on my front porch in nearly full shade, but I don’t remember it coloring up in that situation. Boston Ivy has 3-lobed green leaves changing to a vibrant dark red in autumn. I have not grown it, but my wholesale nurseryman in Houston tells me it colors well even in that mild climate.
I hope you will try some of these varied trees, shrubs, grasses, groundcovers, and vines to introduce fall foliage color into your garden. Please let me know about your successes, and also address me with any questions you might have over time.