How to grow and care Ailanthus (Tree of Heaven)

About Ailanthus (Tree of Heaven)

About Ailanthus (Tree of Heaven): Ailanthus altissima, commonly known as the Tree of Heaven, is a fast-growing deciduous tree native to China. It’s known for its tolerance of poor soil and harsh urban conditions, making it a popular choice for city landscaping. Despite its hardiness, the tree has become invasive in many parts of the world, especially in North America, due to its ability to quickly spread via seeds and root suckers.

Types of Ailanthus (Tree of Heaven):

Ailanthus altissima (Tree of Heaven): The most common species, with large, pinnate leaves and a strong odor when the leaves are crushed. It can reach heights of 40-80 feet and has a wide, spreading canopy.
Ailanthus giraldii: A less common species, native to China and known for having slightly smaller leaves and a more compact form compared to Ailanthus altissima.

Care for Ailanthus (Tree of Heaven):

Light: Prefers full sun, but can tolerate partial shade.
Soil: Adaptable to a variety of soils, including poor, dry, and compacted soils. It can tolerate urban pollution and drought once established.
Watering: While the Tree of Heaven is drought-tolerant, it thrives with regular watering, especially during the establishment phase.
Temperature: Hardy in USDA zones 5-8, the tree can withstand a range of temperatures but is susceptible to frost damage when young.

Pruning Ailanthus (Tree of Heaven):

Timing: Prune in late winter or early spring before new growth begins.
Methods: Remove dead, damaged, or diseased wood. Because the tree can grow rapidly and spread through suckers, prune suckers and root shoots regularly to control unwanted spread. Also, shape the canopy to maintain a central leader and reduce the risk of weak branches.

Propagation of Ailanthus (Tree of Heaven):

From Seed: Ailanthus can be propagated from seeds, which are produced in large quantities during the summer months. Harvest the seeds when they turn brown, then stratify them by refrigerating them for 30-60 days before planting. Sow the seeds in a moist, well-draining soil mix.
From Cuttings: Semi-hardwood cuttings taken in late summer can be rooted in a pot of moist, well-draining soil. Use rooting hormone to improve success rates.
Root Suckers: The Tree of Heaven can also be propagated from its root suckers, which often sprout around the base of mature trees. These suckers can be separated and transplanted to new locations.

Common Issues with Ailanthus (Tree of Heaven):

Invasiveness: Ailanthus is considered an invasive species in many regions due to its aggressive spread via seeds and root suckers. It can quickly outcompete native vegetation and disrupt local ecosystems.
Pests: The Tree of Heaven is susceptible to various pests, including:
- Ailanthus Webworm Moth: The larvae of this moth can defoliate the tree.
- Scale Insects: These pests can infest branches and reduce the tree's vigor.
- Japanese Beetles: These beetles feed on the foliage, creating holes in leaves.
Diseases:
- Verticillium Wilt: A fungal disease that affects the vascular system of the tree, leading to yellowing and wilting of leaves.
- Leaf Spot Disease: Various fungal leaf spots can cause unsightly marks on the leaves but generally don’t cause serious harm.
Odor: The tree emits a strong, unpleasant odor, particularly when leaves are crushed or when flowers bloom.
Weak Wood: Ailanthus is known for its brittle wood, which can be prone to breakage, especially during storms.

FAQ:

Q: How fast does a Tree of Heaven grow? A: Ailanthus is a very fast grower, often gaining 3-6 feet in height per year under ideal conditions.

Q: Is Ailanthus (Tree of Heaven) invasive? A: Yes, Ailanthus is considered invasive in many areas, particularly in North America, due to its rapid spread via seeds and root suckers.

Q: Can I control the spread of Ailanthus? A: Yes, regular pruning and removal of suckers can help control its spread. However, it may still require ongoing maintenance to keep it from becoming invasive in your garden or landscape.

Q: Why is my Tree of Heaven losing leaves? A: Leaf drop could be a sign of stress due to drought, pest damage, or disease. It’s important to monitor for pests like the Ailanthus Webworm Moth or check for signs of disease.

Q: Is Ailanthus toxic? A: While Ailanthus is not typically considered toxic to humans, parts of the tree, especially the sap, can cause skin irritation. It's also harmful to some animals.

Q: How do I get rid of Ailanthus in my garden? A: If the tree has become invasive, remove it by digging out the roots, ensuring all suckers and shoots are removed regularly. Herbicides can be used for more established trees, but it’s important to follow proper guidelines to avoid harm to nearby plants.

By following these care guidelines and keeping an eye on common issues, you can manage your Ailanthus tree in a way that minimizes its potential for becoming invasive and ensures its healthy growth.