Stewartia

( stew - AR - tee - uh )

At-A-Glance Information

This genus of deciduous small trees and shrubs, alternatively spelled Stuartia, needs full sun to partial shade and regular water. These plants are native to Japan and Korea and are slow-growing. Leaves are green and sprout in springtime, and flowers are white, blooming in summer when many other plants have finished flowering. In fall, foliage turns orange and red. In wintertime, branches and trunks of these trees form beautiful silhouettes and have smooth bark that flakes off, giving it a multicolored look. These trees and shrubs are wonderful for woodland gardens and as a foreground specimen (so they can show off their light, beautiful bark).

stewartia Species and Varietals

The genus Stewartia includes between 8 and 20 species and is a member of the plant family Theaceae. It was formally named in 1753 by Carl Linnaeus to honor John Stuart, 3rd Earl of Bute. Unfortunately, he was given the wrong spelling of Stuart's name for his publication, and the genus became commonly known as Stewartia instead of Stuartia. They are closely related to Camellia, as evidenced by their similar blooms. Stewartia grows best in zones 4-6, 14-17, 20 and 21. To find your zone, click here: Zone Map.

Stewartia malacodendron (Silky Camellia, Silky Stewartia, Virginia Stewartia)
These plants are slow growers, eventually forming large deciduous shrubs or small trees, typically reaching between 10 and 15 feet tall (at maximum 30 feet tall). Flowers are white and cup-shaped, blooming from April through August. Woody seed capsules follow flowers.

Stewartia monadelpha (Tall Stewartia, Orangebark Stewartia)
This tree reaches 25 feet tall and 20 feet wide, with branches that are angled towards the sky. Fall foliage is red, and flowers are small. Bark is rich brown when new, and matures to a light tan-brown. These plants can form deciduous shrubs or multi-stemmed trees and prefer temperate rainforest climates. They are native to Japan.

Stewartia ovata (Mountain Camellia)
These small trees are native to low-elevation areas around the southern end of the Appalachian Mountains. They have a limited range, and are considered uncommon. The species reaches up to 16 feet tall, produces green foliage, flaking grey-orange bark, and white flowers in early to mid-summer.

Stewartia pseudocamellia (Japanese Stewartia, Korean Stewartia, Deciduous Camellia)
This species forms a pyramid-shaped tree that reaches 30-40 feet tall and 20-25 feet wide, with leaves that turn orange-red in fall. Flowers are cup-shaped and have orange anthers, and colorful bark.

Stewartia rostrata (Beaked Stewartia)
These plants are fantastic trees for smaller gardens, and are native to southeastern China. They are deciduous, reaching between 13 and 33 feet tall when mature. White (sometimes with a pink flush) Camellia-like flowers bloom from May through July, followed by woody, beaked capsules in September. Bark is grey-brown, and twigs are reddish-brown. Leaves are dark green in spring and summer, transitioning to beautiful hues of dark pink, red, and maroon in fall.

Caring for and pruning Stewartia shrubs

Plant Stewartia in a location that receives partial shade to full sun; in warmer areas, they will need some afternoon shade. Well-draining soil is essential. Stewartia plants prefer acidic soil, with a pH of between 4.5 and 6.5 (no chalk or calcium-rich soil for these guys), and for soil to be kept consistently moist, especially during periods of drought. Apply a layer of mulch around the base of the plant after installation to help retain soil moisture and discourage weed growth. These plants do not need fertilization, but if they seem to be struggling, a springtime application of a slow-release, balanced fertilizer can be used to support the season's growth and flowering. In areas with strong wintertime winds, these plants may need some protection to prevent wind burn and drying out of leaves. Young plants should be pruned to establish a desirable shape. Once established, however, pruning requirements are minimal. Remove spent flowers to encourage more to form and to maintain a neat appearance.

Propagation

Stewartia can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your plant, follow the instructions below:

Propagating Stewartia by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Stewartia by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a plastic sealable bag, peat moss, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds. The seed pods are pretty easy to spot, they're large and are left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Stewartia seeds need to be treated in a few ways before being sown to break seed dormancy. Once harvested, place your seeds in a baggie filled with moistened peat moss, and place the bag in an area where it will stay around 60-65 degrees Fahrenheit. Leave the bag there for 120 days, adding moisture to the bag as needed. After this period has ended, move the bag to your refrigerator for an additional 90 days. Once these treatments have been completed, remove the seeds from their peat moss medium.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area (around 68 degrees Fahrenheit) that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 1-3 months. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Dried seed heads of various species of Stewartia.

Stewartia seeds of various species.

Problems and Pests

Stewartia is generally a disease and pest-resistant genus, however it is still a good practice to keep an eye out for the following common garden pests and issues: