Fall gardens are looking fizzly. This often happens, even without the additional flaying associated with a tropical storm such as Irene. Only the best soil and culture keep a garden looking tiptop all the way through. The nursery-grown chrysanthemums (‘mums), asters, ornamental peppers, fall annuals such as pansies and nemesia, and specialty foliage plants bail out the rest of us.
Why not cut down everything that no longer pleases? Those parts of the garden then become neutral voids, ready for mulch. Other features with continuing color or good looks step to the fore, such as dahlias, caryopteris, or re-blooming daylilies and irises. And if an interesting or colorful autumn garden is high on your list, please consider the following suggestions. One picture is worth a thousand words and one can, of course, Google up plant images. But why not visit Polly Hill Arboretum to see these plants in the flesh?
Switch grass, little bluestem
Heptacodium miconioides, or seven-son flower, in the Caprifoliaceae, is a recent arrival to our gardens, having been introduced by the Arnold Arboretum in 1980. While starting out as a rangy shrub, with room below for an under-planting, a 25-year-old plant will be similar in size to many dogwoods and may be used in similar situations. A specimen could command the late summer garden, for following the flowers are showy sepals that slowly change from green to rosy pink and remain on the plant to extend the overall show. In its flowering phase, well-covered in its white panicles of blossoms, heptacodium could well be taken for a white-flowered crape myrtle, and when the rosy sepals take over, a pink-flowered one.
Many perennial garden asters have fared poorly this year, surprising in that for the most part it has been a spectacular growing season. This is a shame because the tall varieties, so-called Michaelmas daisies, provide those billowing blue, lavender, white, and pink backdrops to the foreground plantings of many fall garden displays. Healthy, shorter, nursery-grown asters may be used to supplement mangy, in-ground plants, but they do not provide the height of grown-in-place plants.
Tall, billowing plants that add late color and a similar feeling of movement to the garden are the bush clovers, or lespedezas. Lespedeza thunbergii ‘Gibraltar’ may be seen swelling over the fence of the Homestead border at Polly Hill Arboretum, right along State Road. It is given nearly a whole page of its own in Manual of Woody Plants (Michael A. Dirr, Stipes Publishing). There are several different forms within this species, three of which are offered in the Spring Meadow (www.SpringMeadow.com) Flowering Shrubs catalogue. As well as ‘Gibraltar,’ L. ‘Samidare,’ — bright fuchsia and four-five feet — and L. ‘Yakushima,’ (L. bicolor) — a violet-purple dwarf of 12 to 18 inches — are offered to the nursery trade. This is a plant that should be more widely known and used.
In bloom at this time all across the countryside is sweet autumn clematis, known by several binomials but currently C. terniflora. It is on the verge of becoming an invasive plant on the Vineyard. Autumn is its season of redemption, when it is to be seen as a gleaming blanket of sweet-scented white flowers atop other hapless host-vegetation and fences from one end of the Island to the other.
Not your everyday invasive clematis but on the contrary, quite rare (not even mentioned in Dirr’s Manual) and to be seen probably only at PHA, is Clematis stans, a shrubby clematis with panicles of nondescript color but highly fragrant blossoms.
Hardy cyclamens C. hederifolium and purpurascens provide autumn garden interest, albeit at ground level. These swept-back little flowers with their decorative leaves are nothing if not subtle but, oh boy, what fun if one has them popping up in one’s garden! Plant in dry shade, such as near the bases of deciduous trees. The corms like a site that is dry in summer. Include plenty of humus and sand for drainage; rot is their enemy.
Osmanthus heterophyllus, the sweet-smelling holly olive or false holly, is a convincing English holly look-alike. Its leaves are arranged opposite, unlike those of true holly, which are alternate. Osmanthus blooms in autumn, also unlike true holly, and the flowers, while small and unobtrusive, are fragrant from early October into November.
The autumn garden is the ideal showcase for ornamental grasses, flowering now. They verge on clichés but always look alluring in open situations with good light. The Pennisetum, Miscanthus, and Imperata (Japanese blood grass) species have entered the arena of controversy with their invasive tendencies, but Panicum virgatum, the native switch grass, and Schizachyrium scoparium, little bluestem, have no such baggage. There are good clones with deep, lovely autumn coloration.
Nearby to our place, line-clearing by a tree service led to an exciting discovery last week. A “hazardous tree,” a large and aged oak, had died and the arborists had started to dismantle its limbs, prior to removing the entire tree. Fortuitously, before felling it, the arborists discovered that the tree’s crevices were full of bats! They left it standing, though limbless; the hazardous tree has become a habitat tree.
Insurance companies have made homeowners and landowners aware of hazardous trees, and fire control policies emphasize the danger of standing deadwood. However, not all dead trees in woodland need to be taken down immediately. Owls, woodpeckers, squirrels, and bats, among others, need trees with cavities, loose bark, and other features, to support their populations. In the case of bats, the choice of a dead tree means eventually having to find another dead tree, when the previous one inevitably falls and returns to humus.