In the Garden: Still Pining Away
By Charles Kidder
In February we looked at the most common native pines that you could either plant in your landscape, or perhaps just enjoy for the character they lend to our local forests. This month we’ll consider a couple of less common natives, as well as the numerous exotic pines that might deserve a place in your garden.
Pitch Pine (Pinus rigida) commonly grows in poor conditions—the New Jersey Pine Barrens, for example—as well as other sandy or rocky soils from New England down the Appalachians. In Virginia it’s found primarily in the mountains, as well as in a few rocky areas of the upper Piedmont. It can grow to almost a hundred feet in ideal conditions, but in the snow, ice and wind of the Blue Ridge’s rocky outcrops, it’s typically a shorter, somewhat scraggly-picturesque tree. And therein lies the rub. If you planted a pitch pine in ordinary “good garden soil,” it could end up as a rather undistinguished specimen. The solution: aesthetic pruning, i.e. employing creative cuts in order to transform your tree into “sculpture.” (You hope…) As an aid to your pruning, Pitch pine is one of the few pines that can sprout needles directly from the trunk, or even from the base of a cut tree. As for cultivars, if you search diligently you might be able to find a few varieties of pitch pine. ‘Sherman Eddy’ grows to only fifteen feet; ‘Winter Time’ has golden needles.
Found only on dry, rocky slopes in the Appalachians from Pennsylvania to Georgia, Table Mountain Pine (Pinus pungens) is a relatively small species, with a rounded, open shape. A distinguishing feature of this pine is its stout cones armed with sharp spines. In some cases, Table Mountain Pines are serotinous, meaning that their cones won’t open and shed seeds without the heat of a fire.
Although the native pines are worthy plants for our landscapes, many of the pines grown as ornamentals in the East are exotic species. Several pines from Europe and Asia, particularly the latter continent, do well in Virginia. And a bit of good news: to my knowledge, none of them are invasive in our area. (Conversely, some of our American species can be quite troublesome when planted abroad.)
The Mugo Pine (Pinus mugo) is very commonly grown north of here, but is somewhat iffy in Zone 7 and southward. Regardless of its survivability, it’s widely sold, so be on the lookout for it. Mugo pine is almost always sold as one of approximately forty dwarf cultivars, shrubs that grow to only a few feet in height. Due to some “confusion” in the nursery industry, at times these shrubs can reach 10’-15’ in height, so they’re not always suitable as foundation plants. The real caveat with Mugo pines is the pests that affect them, notably scale and sawfly caterpillars. The latter are insidious creatures that can quickly consume a pine’s needles. About an inch long and light yellow-green with black dots, they can be very difficult to spot. If you see them on any pine, pick them off and smoosh them.
Pines typically have easily recognizable scaly, blocky bark, but a notable exception is Lacebark Pine, Pinus bungeana. With exfoliating bark that reveals patches of cream, gray and brown against a greenish background—think hunter’s camouflage—Lacebark Pine makes a distinctive specimen tree. Often multi-stemmed, it can ultimately grow to about 50’ with a spread of 35’. ‘Silver Ghost’ is a cultivar with a silvery sheen to the bark.
If the native Eastern White Pine would be too large for your garden, you might consider a few alternatives. Limber Pine (P. flexilis) grows slowly and only to 50” by 35” in cultivation. Its bluish-green needles resemble those of our white pine; the cultivar ‘Glauca’ has needles that are even bluer, and ‘Glauca Pendula’ is a bluish weeping variety. ‘Vanderwolf’s Pyramid’ is an upright form with twisted needles, but watch out; it can grow up to two feet per year. The Japanese White Pine (P. parviflora) grows slowly to about fifty feet and almost as wide, but if that size is too much for your taste, many of the available cultivars stay much more compact. A very graceful tree, the Himalayan Pine (P. wallichiana) has needles that curve downwards, lending a semi-weeping aspect, even though the branches themselves don’t droop. A variety with a gold band on the leaf may be sold either as ‘Oculis Draconis’ (Dragon’s Eye) or as ‘Zebrina’.
Finally, there’s a pine that you should probably avoid putting in your garden, unless you happen to be a horticultural gambler. The Japanese Black Pine (P. thunbergii) is very commonly planted on East Coast beaches owning to its salt tolerance, although it will grow inland and is often used in Japanese-style gardens. A couple of serious problems with this species commonly lead to branch dieback and early death, however, so caveat emptor.
If you’ve gone totally crazy for pines, as well as other conifers, try visiting the website of the American Conifer Society.
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Weed Warning: it may be almost too late for the spring of 2017, but watch out for Hairy Bittercress, Cardamine hirsuta in your yard. Along with its cousin Pennyslvania Bittercress (C. pensylvanica), these winter weeds start to grow in the fall and really take off in the spring. They will quickly flower and set seed, so deal with them immediately if you don’t want them everywhere. As a cress and a member of the Brassicaceae (mustard) family, they are reportedly edible, but as always, I make no representations.