A flourishing tree makes a beautiful garden ornament, but when its flowers are bunched into large, showy clusters, the effect is truly spectacular. This standout feature isn’t common among trees, which is why tree hydrangeas have gained immense popularity.
Tree hydrangeas, in essence, are shrubs similar to their bush counterparts. Their distinctiveness lies in their vertical growth pattern, allowing them to be shaped into a tree-like appearance through careful pruning.
Which hydrangeas grow as trees?
The Hydrangea paniculata is the sole variety that naturally adopts a tree-like form. This species is uniquely suited to being trained into a tree shape, primarily because it doesn’t sprout new branches from its base.
Other hydrangea species are not conducive to tree formation. Despite aggressive pruning, they tend to regrow branches from the ground level, inevitably reverting to a bush-like appearance.
Among the tree-form hydrangeas, the Limelight Hydrangea is notably popular. These are cultivated in nurseries as small, tree-shaped plants, usually reaching heights of 5-6 feet (about 1.5 meters). They quickly mature into compact trees adorned with large, greenish-white flower clusters.
Another variant, the Hydrangea paniculata ‘Grandiflora’, is a more substantial shrub, capable of growing over 20 feet (6 meters) tall. With proper pruning, it can be shaped into a large, blooming tree.
Bush hydrangeas boast a wider array of unique varieties
A significant benefit of choosing bush hydrangeas is their extensive variety of unique types, a feature less prevalent in tree hydrangeas, which are primarily confined to the Hydrangea paniculata species.
A standout example in bush hydrangeas is the Hydrangea macrophylla Arabesque. This variety is distinguished by its pink-crimson petals with unusual sharp tips, a rarity among hydrangeas. Additionally, the petals are elongated and arranged in dual rows, a characteristic not found in tree hydrangeas.
When it comes to diverse color palettes and flower shapes, bush hydrangeas surpass their tree counterparts. Hence, for those seeking exotic and uncommon types, bush hydrangeas, particularly the Hydrangea macrophylla varieties, are worth exploring.
Maintaining a tree hydrangea poses greater challenges
Tree hydrangeas require more effort to maintain due to their natural tendency to revert to a bush-like form. Regular pruning, at least annually, is essential to maintain their tree-like shape.
Neglecting to prune a tree hydrangea over several years results in it resembling an elongated bush atop a single trunk. The lower part becomes bare, with inflorescences appearing only on the higher branches, creating an unusual tree appearance that is not typically seen in nature.
Additionally, managing suckers – thin branches sprouting from the main trunk that consume the plant’s nutrients – is crucial. Regular removal, preferably in the fall, is necessary to prevent them from depleting the plant’s energy during winter.
In contrast, regular bush hydrangeas naturally maintain their bushy shape and require minimal pruning, making them less labor-intensive to care for.
Pros and Cons of Tree Hydrangea
- Unique Aesthetic Appeal: Hydrangea trees offer a distinctive and elegant appearance that stands out in any garden. Their singular trunk and canopy of blooms create a focal point that can enhance the overall landscape design.
- Space Efficiency: Due to their upright growth habit, these trees are ideal for smaller gardens or spaces where ground area is limited. They provide vertical interest without occupying much horizontal space.
- Variety in Height and Scale: Hydrangea trees can be cultivated to different heights, offering flexibility in garden design. They can be kept relatively small or allowed to grow taller, depending on the desired effect and available space.
- Seasonal Interest: In addition to their summer blooms, many hydrangea tree varieties have attractive bark and branch structures that provide visual interest in the winter months.
- Potential for Creative Pruning: For those who enjoy shaping plants, hydrangea trees offer an opportunity for creative pruning, allowing gardeners to sculpt and personalize their appearance.
- Enhanced Air Circulation: The elevated canopy of a hydrangea tree allows for better air circulation around the plant, which can help reduce the risk of fungal diseases commonly seen in denser, bush-type hydrangeas.
- Potential for Top-Heavy Growth: If not pruned correctly, hydrangea trees can become top-heavy, making them vulnerable to damage from strong winds or heavy snow.
- Need for Staking in Early Years: Young hydrangea trees often need staking to support their growth and maintain an upright form, which adds to the initial care requirements.
- Longer Time to Establish: These trees may take longer to establish and reach maturity compared to bush varieties, delaying the gratification of seeing them fully bloom.
- Less Hardy in Some Climates: Depending on the variety, some hydrangea trees may be less hardy in extreme climates, requiring more protection in winter or more water in hot temperatures.
- Higher Cost: Hydrangea trees can be more expensive than their bush counterparts, both in initial purchase and in ongoing maintenance costs.