Turtlehead (Chelone obliqua) is a clump-forming perennial wildflower native to eastern North America. Its hooded flowers look similar to snapdragon blooms. The flower gets its common name from its resemblance to a turtle's head, but the genus name Chelone dates back to ancient Greece mythology. As the story goes, a nymph by the name of Chelone elected not to attend the marriage of Zeus and Hera, so she and her house were tossed into a river, where she transformed into a tortoise who carried her house on her back.
The different turtlehead species share similar growing conditions but vary in their size and appearance, bloom color and time, and native range. Red turtlehead (Turtlehead obliqua) blooms in midsummer or early fall. It favors boggy areas but can be cultivated in a partially shaded home garden. The plant's opposing dark green, oval leaves are slightly toothed, and its stems stand upright, even when in flower.
Turtlehead is best planted in the spring or summer to give the plant time to establish itself. A slow-growing plant, it is generally hardy in USDA zones 3 through 9. The plant can remain in bloom for three to six weeks, making it well worth the wait for late-season color.
|Common name||Turtlehead, red turtlehead|
|Botanical Name||Chelone obliqua|
|Plant Type||Herbaceous, perennial|
|Mature Size||2–3 ft. tall, 1–2 ft. wide|
|Sun Exposure||Full, partial|
|Soil Type||Rich, moist|
|Soil pH||Neutral, acidic|
|Bloom Time||Summer, fall|
|Flower Color||Pink, purple, white|
|Hardiness Zones||3–9 (USDA)|
|Native Area||North America|
Turtlehead plants prefer moist soil in a location with filtered sun, but they also have a good tolerance for partially shady conditions. One thing they do not like, however, is dry soil. In bright sun, a layer of leaf mulch will help keep the soil cool and moist. When planted in a shady area, they may require staking to prevent them from flopping over, though this is rarely necessary in sunnier locations.
As a woodland flower, turtlehead blooms best in full sun but tolerates partial shade—the setting is most similar to its natural environment, where it typically grows in the filtered light beneath a canopy of trees. However, the plant can grow in full sun as well, as long as its soil is kept continually moist. Pink turtlehead (C. lyonii) is considered the species most tolerant of bright sun.
Turtlehead plants prefer moist, organically rich soil, with a neutral soil pH level between 6.0 and 7.0.
Keep your turtlehead plants continually moist while the plants set root and throughout their growing and blooming season. As a general rule of thumb, turtlehead grows best when it gets regular water, and it is especially important during the first year as the plants establish themselves. The less water stress they suffer, the more they will thrive.
Temperature and Humidity
These plants prefer mild, moist conditions and will not do well in hot, arid climates. In warm climates, give the plants some shade and mulch the ground with a thick layer of leaf mulch or another organic material.
Don't feed your turtlehead plants during their first year of growth. After that, a yearly spring feeding with a balanced liquid fertilizer is recommended to encourage blooms. For the amount to use, follow the product label instructions.
Types of of Turtlehead
There are several species, as well as hybrids and cultivars, of turtlehead. Some of the more well-known ones include:
- Chelone obliqua 'Alba': White-flowered cultivar that blooms in late summer.
- Chelone obliqua 'Tiny Tortuga': A dwarf cultivar with pink-rose blooms in late summer to early fall.
- Chelone glabra (white turtlehead or balmony): While not as showy as some of the other turtleheads, white turtlehead produces ivory blooms and makes for a great garden accent. It blooms in late summer through early fall.
- Chelone glabra 'Black Ace': A cultivar named after its almost black foliage in the spring. It blooms in late summer.
- Chelone Iyonii (pink turtlehead): This variety has long stems that give the species an open, bushy appearance. Its flowers range from light pink to deep rose to red, and it's more tolerant of dry conditions than the other turtleheads. Bloom time is in the late summer.
- Chelone Iyonii 'Hot Lips': Pink flowers in late summer and fall
If your plants start to get floppy, prune or pinch back the stems of established plants in mid-spring—this will cause the plant to become more compact, but fuller and showier.
Turtlehead is easily propagated by division. The best time in cooler climates is early spring when its shoots stand at least one inch high. In warmer zones you will have the best luck dividing in early fall.
- Lift the clump with a shovel. Separate it into smaller clumps that have at least three established shoots in each section.
- For each section, dig a hole the depth of the clump and place the clump in it. Backfill it with soil and gently press down the areas around the plant.
- Water it well and keep the soil moist at all times until the new plant is established. Hold off on feeding your divisions until their second year.
How to Grow Turtlehead From Seed
Although often planted from potted nursery plants, turtlehead is actually relatively easy to grow from seeds. Some species, such as Chelone glabra, require cold stratification to germinate. The seed package usually indicates whether cold stratification is required, and for how long.
The best time to seed red turtlehead, indoors or out, is in the spring. Gardeners in cold climates can start seeds indoors on a sunny windowsill, then transplant them into the ground as seedlings well after the last frost.
Sow seeds indoors using trays or cell packs filled with moist, sterile potting soil. Gently press the seeds into the soil and keep them constantly moist. The seeds need light to germinate. Germination will occur in three to five weeks. Long after the final frost, and when seedlings are at least six inches high, prepare your outside bed by working compost into the soil with a rake. If soil is compacted, add peat moss for aeration before transplanting the seedlings into the garden. Make sure to harden off seedlings for a week before planting outside.
Common Pests and Diseases
Turtlehead is rarely bothered by insects or diseases.
How to Get Turtlehead to Bloom
Once your turtlehead plant has established itself, pinch the tips of each shoot to train the plant to grow bushy and produce showy blooms. Since turtlehead blooms late in the season, there is no reason to deadhead spent flowers. You can leave the flowers to dry, and then collect the seeds if you like. The seeds appear in pea-shaped pods.
Common Problems with Turtlehead
The plant can develop powdery mildew due to moisture fluctuations in its environment. Keeping the plants evenly moist and watering them at the base of the plant (versus on the foliage) should alleviate this problem. Plants in shade may need staking.
Do turtlehead plants spread?
Over time, the rhizomes of the turtlehead slowly form clumps about 1 foot wide but it does not spread much wider than that.
Are turtleheads invasive?
Turtleheads are native to North America and as such, they are not invasive. In fact, they are important host plants for Baltimore checkerspot butterflies whose larvae feed on the leaves. Turtlehead also attracts bees and hummingbirds so it is an excellent plant for a pollinator garden.
Is turtlehead plant toxic to dogs?
Turtlehead is not known to be toxic to dogs.