The terms "lilac tree" and "lilac bush" are often used interchangeably, leading to some confusion. While the distinction isn't strictly botanical, there's a practical difference based on the plant's growth habit and how it's trained. Essentially, there's no separate species called a "lilac tree." All lilacs are shrubs, but some can be trained to resemble small trees.
What is a Lilac Bush?
Most lilacs (genus Syringa) naturally grow as multi-stemmed shrubs. They develop multiple canes (woody stems) from the base, creating a bushy, rounded form. This is the typical image that comes to mind when we think of lilacs. These bushes can range in size, depending on the cultivar, from a few feet tall to as much as 15 feet or more, but they maintain their shrub-like structure.
Can Lilacs Be Grown as Trees?
Yes! While naturally bushy, lilacs can be trained to grow as small trees. This involves selecting a single strong central stem as the trunk during the plant's early years and pruning away all competing stems. Regular pruning is essential to maintain this tree-like form, preventing the lilac from reverting back to its natural multi-stemmed habit. This process is called standards.
How to Train a Lilac into a Small Tree?
Training a lilac as a standard requires patience and consistent pruning. Here's a general overview:
- Start Young: Begin with a young lilac plant, ideally one that already has a dominant central stem.
- Select a Central Leader: Identify the strongest, straightest stem and remove all others at ground level.
- Regular Pruning: Prune regularly throughout the growing season, removing any side shoots that develop below the desired height of the "trunk."
- Shape the Crown: Once the desired trunk height is reached, allow the top of the plant to branch out, shaping it into a small, rounded crown.
What are the Advantages of a Lilac "Tree"?
- Aesthetic Appeal: A lilac standard offers a unique and elegant look in the landscape, especially in smaller gardens where a large bush might be overwhelming.
- Better Air Circulation: The open structure of a tree-form lilac allows for better air circulation, potentially reducing the risk of fungal diseases.
- Easier Access to Flowers: The raised flowers are easier to appreciate and enjoy compared to a low-growing bush.
What are the Disadvantages of a Lilac "Tree"?
- Increased Maintenance: Maintaining the tree form requires more effort and regular pruning than letting the lilac grow naturally as a bush.
- Potential for Wind Damage: A single-stemmed tree is potentially more vulnerable to wind damage than a multi-stemmed bush.
- Potential for Top-Heaviness: If not pruned properly, the top of the tree might become too heavy, leading to instability.
What's the Difference in Care?
The basic care requirements for a lilac tree and a lilac bush are similar. Both need well-drained soil, full sun, and regular watering, especially during dry periods. Fertilizing in spring is also beneficial for both. The primary difference lies in the pruning—a lilac tree requires more structured pruning to maintain its form, while a bush typically needs less frequent and more general pruning.
So, is it a tree or a bush?
Ultimately, whether you call it a lilac tree or a lilac bush depends on how it's grown. Botanically, it's a shrub. But with a little training and effort, you can create a beautiful lilac tree.
