Among the stars of the fall garden is a truly unique perennial, the turtlehead (Chelone spp.). What I love about this plant, besides its long-lasting flowers, is its perfect behavior. It never runs, flops, or fades, standing firm in the worst wind and the deepest shade. If only all the plants were as well behaved!
At the very end of the summer and throughout the fall, fat tubular pink to white flowers appear on short spikes atop each stem. The blooms are odd enough in appearance, almost closed at the tip with an opening resembling a beak. They’re said to look like the head of a turtle, whence both the common name and the botanical one, as Chelone (pronounced “kay-LOH-nee”) is Greek for turtle.
The curious flower is designed to let only the strongest pollinators enter, notably bumblebees and hummingbirds. Even so, you’ll often see butterflies stopping by, trying to steal a bit of nectar with their long proboscis.
Turtleheads leaves have opposite leaves with each pair placed at a 90 degree angle to the pair below, giving the effect of a cross when you look at the plant from above. Their stem is square, a trait unusual in their plant family, the Plantaginaceae (foxglove family), but one shared with at least one close relative, the obedient plant (Physostegia virginiana).
There are only four species of turtlehead, all from eastern North America. The following three are the most widely available to home gardeners.
Red Turtlehead (C. obliqua)
In spite of its common name, the deep pink flowers of this species not really much darker than those of the so-called pink turtlehead (C. lyonii) with which it is often confused. This species is native to eastern and central United States, although absent from New England.
Red turtlehead forms dense clumps of upright unbranching stems bearing large, lightly toothed, lanceolate leaves of a very dark green shade. The leaves have a short petiole, an apparently minor detail, but one worth pointing out, as that is what distinguishes it from C. lyonii.
Red turtlehead reaches about 2 to 3 feet (60 to 90 cm) in height. As with the other turtleheads, it begins to bloom at the very end of summer and continues for a good 2 months, right through fall in many locations. It is hardy to zone 3.
There is also a supposed white-flowered cultivar of this species called ‘Alba’… but it is likely just C. glabra, described below.
Pink Turtlehead (C. lyonii)
Essentially identical to C. obliqua from a gardener’s point of view, with the same pink blooms, you can identify pink turtlehead by the slightly longer leaf petioles. It is also somewhat taller (2 to 4 feet/60 to 120 cm) than C. obliqua.
The most common cultivar of this species is ‘Hot Lips’, which is a more compact plant: about 2 to 3 feet (60-90 cm) in height. Its flowers are a darker pink and its stems are reddish.
‘Tiny Tortuga’ is a 2014 introduction, with dark pink flowers. Very dwarf, it reaches only 14 inches (35 cm) high.
There is also another dwarf variety, ‘Pink Temptation’, about 16 inches (40 cm high). All these plants are hardy in zone 3.
White Turtlehead (C. glabra)
This is the most widely distributed turtlehead, found throughout much of eastern and central North America well into Canada. It is easily distinguished from the others by its white to white tinged pink flowers. Also, the leaves are narrower and sessile (they have no petiole at all).
Although a plant of swampy woodlands in the wild, white turtlehead grows very well in ordinary garden soils. Its height is highly variable, from 3 to 6 feet (90-180 cm): it grows tallest in water-logged soils. Although native well into the North, it seems no hardier than the southern species: zone 3.
I find this species the least interesting turtlehead for the flower border, because its flowers are less dense, tend to brown quickly and its habit is more open and less sturdy. It is even a bit invasive.
There is also a cultivar, C. glabra ‘Black Ace’, with extra dark foliage, almost black, and the denser flowers. Also zone 3.
Japanese False Turtlehead (Chelonopsis yagiharana)
Chelonopsis is the Asian counterpart of the genus Chelone, with a very similar habit and foliage, but its tubular flowers are distinctly trumpet-shaped and thus look nothing like a turtlehead. The lower lobe is substantially longer and wider than the upper one.
There are over 15 species, but the only one I have seen offered is C. yagiharana, from Japan. This species is quite compact: about 1 to 2 feet (30-60 cm) in height. Its exact hardiness is not known yet, but it seems to perform well in zone 4. It is as yet rarely offered.
One nice thing about turtleheads is that they are a snap to grow and you never hear complaints about them.
They like soil rich in organic matter that is always a bit humid. They tolerate poorly drained soils and can thus grow along the edge of a water garden. Water them in case of drought, however, as their drought tolerance is limited. A good mulch to keep their soil more evenly moist would be appreciated.
They are not very heavy feeders and will get along fine with an annual application of compost.
Turtleheads seem to grow equally well in sun or shade… and how often can you say that about a plant! In the wild, they are often found in dense forests where little light penetrates, but also in swamps out in full sun. Just make extra sure they are well-mulched if you want to grow them in a sunny location.
Most species of turtlehead form a dense clump that expands ever so slowly in diameter, so keeping them in their place is not complicated. White turtlehead is the exception, a faster grower with a more invasive nature and may require more frequent division.
For quick and easy multiplication, try taking stem cuttings. You can also divide the plants, preferably in the spring, but also in the fall.
Turtleheads are the primary host of the beautiful Baltimore Checkerspot butterfly, but the damage is usually limited to a few leaves and thus easily forgiven. And even though they often they grow in damp environments where slugs are numerous, the latter seem to have no interest in turtleheads.
Sadly, white-tailed deer are crazy about this plant: if you have a problem with this mammal in your yard, turtleheads will not be a good choice for your flowerbeds!
Where to Find Them?
Turtleheads are quite widely available and most garden centers and nurseries will offer at least one variety, although you’re not likely to find the whole range of species and cultivars in a single spot. For specific cultivars you can’t find locally, try a mail order source.
Turtleheads: their odd name belies an ease of culture well worth discovering, certainly one of the best fall-blooming perennials.