Clusia is a large genus of trees and shrubs native to tropical America. The plants stand out by their branches, which grow horizontally, and their leaves, which are thick and tough. There are about 150 Clusia species, but Clusia rosea, or the autograph tree, is the only one commonly cultivated. It is notable for its tendency to grow on top of other plants, often strangling them, therefore it is widely considered to be an invasive species outside its native range. Another unusual quality, this species is part of the only genus of plants capable of absorbing carbon dioxide at night.
The moderate- to fast-growing autograph tree has stiff, dark green or olive-colored leathery leaves that grow to about 8 inches long. The leaves are tough enough that they can be carved into, hence the common name “autograph tree.” It has long flower heads with pink or white flowers that bloom in the summer, followed by small green fruits that ripen to black and eventually split open to reveal bright red seeds. The seeds are very attractive to birds and other fauna. The autograph tree is commonly grown as an indoor plant. Where it is able to survive outdoors—in zones 10 and 11—it can be planted in spring or fall.
The plant is toxic to humans, and toxic to dogs and cats.
|Common Name||Autograph tree, copey, balsam apple, pitch apple|
|Botanical Name||Clusia rosea|
|Plant Type||Shrub, tree|
|Mature Size||8 to 25 ft. tall, 8-10 ft. wide|
|Soil Type||Sand, clay, loam, well-draining|
|Soil pH||Acidic, neutral|
|Flower Color||White, pink|
|Hardiness Zones||10-11 (USDA)|
|Toxicity||Toxic to humans, and toxic to pets.|
Watch Now: How to Grow and Care for the Autograph Tree
Autograph Tree Care
The autograph tree tends to spread out fairly wide as it grows. It should be pruned about once a year, in early spring, to keep it nicely formed. Fertilization will help it grow fully. The plant makes an excellent hedge because of its dense growth habit and its minimal maintenance needs. Alternatively, if you grow it tall as a tree, you can underplant things close to its base. The autograph tree is salt-tolerant and can be grown in exposed positions near the ocean.
Grown as a houseplant, the autograph tree needs warmth, humidity, and a moderate amount of sunlight. A room with a south- or west-facing window is ideal for giving it a few hours of bright sun plus some indirect light and some shade.
Full sun is best, but this plant can tolerate partial shade as well. When it is grown indoors as a houseplant, it will cope with medium light levels and some degree of shade.
A sandy, soft, loose, well-draining soil is best. It should be fertile and rich in organic matter. When growing in pots, blend the potting mix with a small amount of growing medium for orchids.
The autograph tree should be watered regularly for the first year or so until the plant is fully established. You can scale back its water after that, although regular watering will help it grow more fully. This species is fairly drought-tolerant, but you should never let the soil get completely dry.
When grown as a houseplant, it typically needs water once a week in summer and three times per month in winter.
Temperature and Humidity
This plant can be kept outside only in tropical areas, as it will not tolerate temperatures below 50 degrees Fahrenheit. Indoors, it prefers temperatures between 60 and 85. It also prefers high humidity. If you have an indoor container plant, you can place it on a shallow gravel tray filled with water and mist regularly.
Fertilize three times per year in the spring, summer, and fall. Use organic, granular fertilizer. Or, you can fertilize more frequently but must use an evenly balanced diluted liquid fertilizer. For the amount to use, follow the product label instructions.
Propagating the Autograph Tree
Clusia rosea is a hemiepiphyte, a plant that spends the first part of its life cycle as an epiphyte growing on another tree or structure without being parasitic, It grows toward the ground until it eventually plants itself in the soil. Over time, it overgrows and eventually suffocates its host. This growth pattern is what has made the autograph tree a dangerous invasive species in several tropical areas.
The autograph tree can be grown fairly easily from stem cuttings, which is the recommend method of propagation (the seeds are not readily available for purchase).
- Using sharp pruners, cut a couple of strong stems just below the buds, about 4 to 6 inches in length.
- Strip the cut end of the stems of its leaves. Make sure that the top has at least a couple of healthy leaves.
- Fill a 1-gallon container with potting mix. Using a pencil or a stick, poke holes in the soil, one for each cutting. Insert about one-third of the stem into the soil. Water it well until the soil is evenly moist.
- Keep the pot in a warm, moist place and water it regularly so it never dries out.
- New growth is an indicator that the cutting has developed roots. If both cuttings have rooted, keep the stronger one and cut the other one at ground level (do not pull it out, or you risk damaging the tender roots of the other plant).
- If you intend to plant the autograph tree in the landscape, leave the new tree in the container until it has visibly grown in height.
Potting and Repotting
Due to its quick growth, Clusia rosea can often overgrow its container. To repot, lift out the root ball as a whole and move to a larger container that can accommodate the root system. As the plant matures, it may become too large to be kept in containers at all unless it is well-pruned. If the climate is suitable, large plants can be replanted outdoors.
The autograph tree is a tropical plant that does not tolerate frost. If you live in a climate where winter temperatures, even occasionally, fall below freezing, growing it in the landscape is not an option. Container-grown plants need to be brought indoors and kept like a houseplant when the temperature drops below 50 degrees Fahrenheit, as the tree stops growing in cool weather.
How fast does Clusia rosea grow?
The growth rate of the plant depends on soil type, light, and temperature. In an outdoor setting, it is not unusual for the tree to grow 12 inches per year.
Why is my autograph tree turning brown?
Brown, yellow, or discolored leaves, or a brown, mushy stem can be signs of overwatering, which can lead to root rot. If the stem’s base turns brown but remains solid and wood-like, the browning is part of the natural aging process.
Can you eat the fruit of an autograph tree?
No, the fruit and all parts of the plant are toxic to humans, cats, and dogs. Birds and other wildlife, on the other hand, eat the seeds without ill effects, which has led to the uncontrolled spreading of the tree in Hawaii where it is considered an invasive species.
Kocurek, M., Kornas, A., Pilarski, J. et al. Photosynthetic Activity of Stems in Two Clusia Species. Trees, 29,1029–1040, 2015, doi:10.1007/s00468-015-1182-7
Smith. James P. Jr. Poisonous and Injurious Plants of the United States: A Bibliography. Digital Commons @ Humboldt State University.