Skeleton flower is a somewhat unusual woodland perennial in the same family as the mayapple. Large, umbrella-like leaves cover the crown of the plant, making for an attractive ground cover when the plant colonizes the shady areas beneath trees. But there is one unique effect that makes the skeleton flower a true conversation piece: In June or July, skeleton flower produces tiny white flowers that are initially ordinary, but then turn colorless and clear as glass when touched by rain.
This happens because the petals of the skeleton flower are so thin that they become transparent except for the intricate skeleton-like veining. As the flowers dry up, they turn a faded white. In early autumn, the reddish seed stalks develop clusters of bright blue berries, also quite an eye-catcher.
Skeleton flower is a slow-growing species that is normally planted in early spring or early fall. It can take years to grow into a small colony, but once established, it is a long-lived plant.
|Common Name||Skeleton flower, umbrella leaf, Asian umbrella leaf|
|Botanical Name||Diphylleia grayi|
|Plant Type||Perennial, herbaceous|
|Mature Size||12–18 in. tall, 1–3 ft. wide|
|Sun Exposure||Partial, full shade|
|Soil Type||Sandy, loamy|
|Soil pH||Acidic to neutral (4.5 to 7.0)|
|Hardiness Zones||4–9 (USDA)|
|Native Area||China, Japan|
Skeleton Flower Care
Where possible, it's best to buy established nursery plants from a nursery, but skeleton flower is an unusual specimen that can be hard to find outside of specialty nurseries—and they often sell out of limited stock very quickly. Sometimes the only option is to plant from purchased seeds, though this can be a tricky operation, as the seeds don't germinate well and it can take a full year to develop a viable plant.
Skeleton flower is a woodland native to the colder mountainous regions of China and Japan, and to grow this flower you will need to mimic those conditions: shady understory area under the canopy of deciduous trees, protected from strong winds and growing in consistently moist, undisturbed soil that is rich in organic material from fallen tree leaves.
If you do manage to provide the right location, skeleton flower is quite easy to maintain. Throughout the growing season, just remove the dead foliage so that the new leaves can unfold without hindrance. Skeleton flower is not commonly affected by any serious pests or diseases, nor are there any common cultural complaints.
Skeleton flower is very sensitive to harsh sunlight. It requires a shady location, preferably woodland, where it is fully protected from the hot midday and afternoon sun. Any direct sunlight it receives should be morning sun.
The soil should be deep, rich in humus, and consistently moist yet very well-drained. A sandy soil with large amounts of organic material is ideal. To mimic the plant's native habitat, where skeleton flower gets a constant supply of decaying organic matter, mulch the plant with an ample amount of compost or leaf mold every year.
Skeleton flower requires consistent moisture so select a location with naturally moist soil. During a dry spell, water it slowly and deeply, preferably by drip irrigation or soaker hoses.
Temperature and Humidity
Hardy in zones 4 to 9, skeleton flower needs a relatively cool, temperate climate, and it likes humid air. It won’t do well in regions with hot, dry summer weather. The plant dies back in winter and requires a winter chill period to reset itself. In colder climates, covering the plant crowns with a thick layer of organic mulch helps to protect the roots from frost-freeze cycles that can be deadly.
If there is not enough natural organic matter from fallen leaves, you can add a complete fertilizer, diluted to half strength, in the early spring.
Propagating Skeleton Flower
Diphylleia grows stems from its thick underground rhizomes. The best way to propagate them is by dividing these rhizomes. Division every few years will also help rejuvenate overgrown root clumps. Here's how to do it:
- In early spring, use a shovel to dig up the entire rhizome clump.
- Use a sharp knife to divide the clump into sections, each section including a portion of the root crown.
- Replant in the desired location, with the crown side of the division just barely covered with soil. Plant the divisions fairly close together if your goal is to speed up the creation of a colony.
Be patient, as these slow-growing plants will take several years to reach maturity and establish a new colony.
How to Grow Skeleton Flower From Seed
Growing skeleton flower from seed is notoriously unreliable, but sometimes it is the only available method, since nursery-grown plants may not be available. The seeds will need cold stratification, so it's best to store them in the refrigerator for several months before planting them at a shallow depth in trays filled with a seed-starter mix in late winter, about six weeks before the last frost date. Keep the trays moist, in a bright location but out of direct sunlight. Be prepared for some disappointment, as only a fraction of the planted seeds will germinate and sprout. The seedlings can be transplanted into the garden after all danger of frost has passed.
Another method is to plant the seeds directly in the garden in fall, allowing winter temperatures to perform the cold stratification.
Potting and Repotting Skeleton Flower
Gardeners who live in colder regions (zone 3 or colder) who are looking for a unique specimen can grow skeleton flower as a potted plant, using ordinary commercial potting soil amended with plenty of compost. The pot can be of any material, provided it has good drainage. The plants are kept outdoors during the growing season, then moved to a sheltered location (cold frame or unheated porch) and allowed to go dormant for the winter. With spring arriving, slowly increase the watering and acclimate the plants over several days before moving the containers outside permanently for the summer. These are slow-growing plants that will require repotting only rarely.
Do not try to grow skeleton plant as a traditional houseplant, however, as it needs a cold-induced dormant period to flower.
When grown within its accepted hardness range, these plants require little winter protection, but a thick layer of mulch may be some help in northern climates (zone 4). Don't bother to clip off the leaves or plant stalks, as the dead plant material simply becomes part of the mulch layer that these plants need to thrive.
How to Get Skeleton Flower to Bloom
Be patient with skeleton flower, as it can take up to three years for a young plant to reach flowering maturity. Poor flowering on well-established plants is usually traced to inconsistent moisture. Skeleton flowers like to be damp, so make sure the soil does not dry out. Because tree roots can absorb a lot of ground moisture, a skeleton flower colony planted beneath shade trees may require twice-weekly watering during dry weather.
Less frequently, lack of nutrients can cause poor flowering. Feeding is usually not an issue for these plants if the soil is very fertile and heavy in organic material, but in more barren soil, a good dose of spring fertilizer may stimulate the plants into producing more flowers.
How can I use this plant in the landscape?
Skeleton flower finds its best (perhaps only) use in shady woodland gardens with humusy, sandy soil. Because it is so slow-growing, skeleton flower is best planted in groupings and not as an individual specimen. The clumps of large, green foliage make for an attractive ground cover, but it can take years for a thick colony to form.
Are there other Diphylleia species I should know about?
There are two other Diphylleia species but only Diphylleia grayi has the stunning skeleton effect. But other species do make attractive groundcovers in shady woodland locations. American umbrella leaf (Diphylleia cymosa) is a plant native to the southeastern United States and the southern Appalachian mountains. Another species native to China and Japan (Diphylleia sinensis) is known for the shiny bronze color of the emerging foliage in the spring.
How long does skeleton flower live?
As is often the case with slow-growing plants that grow from rhizomatous roots, skeleton flower can live for decades when it colonizes under ideal conditions. But these plants are very sensitive to lack of moisture, so to get this kind of longevity, you'll need to closely monitor their soil moisture.