Looking for plants that pull double duty in your garden? The line between shrubs and trees isn't always clear-cut. Many woody plants can be trained to grow as either, giving you flexible options for your landscape design.
Some shrubs naturally develop into tree forms with a little pruning and patience. These "trubs" offer the perfect solution for small gardens where full-sized trees won't fit, or for creating stunning focal points with multiple seasons of interest.
1. Japanese Maple (Acer palmatum)
Japanese maples naturally grow with a beautiful tree-like form despite being classified as large shrubs. Their delicate, lacy foliage transforms through the seasons, starting with bright spring greens, deepening to rich summer tones, and finishing with fiery autumn colors. The sculptural branching pattern creates winter interest even after leaves drop.
These versatile plants work beautifully as specimen trees in smaller gardens. Most varieties reach 15-25 feet tall at maturity, though dwarf cultivars stay under 10 feet. Plant them where their distinctive silhouette can be appreciated year-round. Japanese maples prefer partial shade in hot climates but tolerate full sun in cooler regions.
Japanese Maple Care Requirements
Growing Japanese maples as tree forms requires minimal intervention. They naturally develop an elegant branching habit without much pruning. If shaping is desired, prune in late winter while the plant is dormant to minimize sap loss. Remove crossing branches and any growth that disrupts the graceful form.
These plants prefer consistently moist, well-drained soil rich in organic matter. Apply a layer of mulch to maintain soil moisture and suppress weeds, but keep it pulled back from the trunk to prevent rot. Japanese maples don't tolerate drought well, so regular watering during dry spells is essential, especially for newly planted specimens.
2. Crape Myrtle (Lagerstroemia indica)
Crape myrtles transition beautifully from shrub to tree form with some strategic pruning. Their spectacular summer flowers last for weeks in shades of pink, purple, red, or white. The smooth, peeling bark reveals cinnamon-colored underbark that provides striking winter interest after leaves drop.
These versatile plants thrive in hot, sunny locations where many other flowering trees struggle. Most varieties reach 15-25 feet tall when trained as trees, though newer cultivars offer more compact options. The multi-stemmed growth habit creates an interesting architectural element in the landscape, especially when underplanted with complementary perennials.
Training Crape Myrtles as Trees
Transforming a crape myrtle into a tree form requires selective pruning during the dormant season. Start by identifying the strongest 3-5 stems to retain as main trunks. Remove all other stems at ground level, along with any suckers that emerge from the base throughout the growing season.
As the plant matures, gradually remove lower branches to create clearance beneath the canopy. This process, called "limbing up," creates the distinctive tree form while showcasing the beautiful bark. Avoid severe topping or cutting back all branches to the same height; a harmful practice sometimes called "crape murder" that damages the plant's natural form.
3. Rose of Sharon (Hibiscus syriacus)
Rose of Sharon naturally grows as a multi-stemmed shrub but easily transforms into a charming small tree. This hibiscus relative produces an abundance of hollyhock-like flowers from midsummer through fall when many other plants have finished blooming. The trumpet-shaped blooms come in white, pink, purple, or blue, often with contrasting centers.
With proper pruning, Rose of Sharon develops a vase-shaped tree form reaching 8-12 feet tall. Its late-season flowering makes it valuable for extending garden interest. Plant this versatile "trub" where its blooms can be enjoyed up close, as they attract numerous pollinators including hummingbirds and butterflies.
Rose of Sharon Pruning Techniques
Converting Rose of Sharon to tree form works best with young plants. Select one strong central stem to become the main trunk and gradually remove competing stems at ground level. As the plant grows, remove lower branches to create clear trunk space beneath the flowering canopy.
Prune in late winter or early spring before new growth emerges. Rose of Sharon blooms on new wood, so winter pruning won't sacrifice flowers. Remove any dead, damaged, or crossing branches, and thin interior growth to improve air circulation. This pruning regime also helps prevent self-seeding, as Rose of Sharon can become invasive in some regions.
4. Viburnum (Viburnum spp.)
Several viburnum species make excellent small trees when properly trained. These adaptable plants offer multi-season interest with fragrant spring flowers, summer berries that transition from green to red to blue-black, and outstanding fall foliage. The layered branching pattern creates winter interest even after leaves drop.
Larger viburnum species like Korean Spice Viburnum (Viburnum carlesii) and Doublefile Viburnum (Viburnum plicatum f. tomentosum) work best as tree forms. When trained, they typically reach 12-15 feet tall with similar spread. Their natural horizontal branching creates an elegant silhouette without extensive pruning.
Viburnum Selection for Tree Forms
When selecting viburnums to grow as trees, choose varieties with natural upright growth habits. Nannyberry (Viburnum lentago) and Blackhaw Viburnum (Viburnum prunifolium) develop tree-like forms naturally, reaching 15-20 feet tall at maturity. These native species offer excellent wildlife value alongside their ornamental qualities.
For smaller gardens, consider compact varieties like 'Summer Snowflake' (Viburnum plicatum f. tomentosum 'Summer Snowflake'), which grows to about 8 feet tall. This repeat-blooming selection produces horizontal tiers of white flowers throughout the growing season, creating a distinctive architectural presence when grown as a small tree.
5. Lilac (Syringa vulgaris)
Common lilacs naturally grow as large shrubs but develop beautiful tree forms with patient training. Their intensely fragrant spring flowers create a sensory experience unmatched by many landscape plants. The heart-shaped leaves provide a lush green backdrop throughout summer before turning yellowish in fall.
Tree-form lilacs typically reach 15-20 feet tall with rounded canopies. Their gnarled, multi-stemmed trunks develop character with age, adding winter interest. Position lilac trees where their fragrance can be appreciated near patios or entryways. For smaller spaces, dwarf Korean lilacs (Syringa meyeri) can be trained as miniature trees.
Lilac Training Methods
Creating a tree-form lilac requires gradual pruning over several years. Begin with a young plant and select 3-5 strong stems to form the main structure. Remove all other stems at ground level and continue removing suckers as they appear throughout the growing season.
As the selected stems grow taller, gradually remove lower branches to create 3-4 feet of clear trunk. Prune immediately after flowering to avoid cutting off next year's flower buds. Established lilac trees need minimal pruning beyond removing spent flower clusters and occasional thinning to maintain air circulation within the canopy.
6. Witch Hazel (Hamamelis spp.)
Witch hazels make exceptional small trees with their spreading, horizontal branching pattern. These understated plants burst into bloom during unlikely seasons, winter or very early spring, when their spidery flowers unfurl in shades of yellow, orange, or red. The ribbon-like petals emit a sweet fragrance that carries on winter air.
As trees, witch hazels develop an open, broad-spreading form reaching 15-20 feet tall and wide. The smooth gray bark provides subtle beauty throughout the year. Plant witch hazel where its winter flowers can be appreciated from indoor viewing areas. Fall foliage turns brilliant gold, orange, or red before dropping to reveal the elegant branch structure.
Witch Hazel Varieties for Tree Form
For tree forms, choose larger witch hazel species like common witch hazel (Hamamelis virginiana) or Chinese witch hazel (Hamamelis mollis). These develop stronger central leaders naturally. Japanese witch hazel (Hamamelis japonica) and its hybrids offer the most colorful and fragrant winter flowers.
Train witch hazels to tree form by selecting a strong central stem and removing competing leaders. Clear the lower trunk by gradually removing branches from the bottom up. Witch hazels require minimal pruning once established. Any necessary shaping should be done immediately after flowering to avoid removing next year's flower buds.
7. Hydrangea (Hydrangea paniculata)
Panicle hydrangeas transition beautifully from shrubs to small trees, creating spectacular summer displays. Their cone-shaped flower clusters emerge white in summer, gradually transitioning to pink or rusty-red as they age. The dried flower heads persist through winter, adding textural interest to the dormant garden.
Tree-form panicle hydrangeas typically reach 8-15 feet tall, depending on the cultivar. The weight of the massive flower heads creates a gracefully arching silhouette as the season progresses. Popular varieties for tree forms include 'Limelight', 'Pinky Winky', and 'Tardiva', all of which produce abundant blooms on new wood.
Hydrangea Tree Maintenance
Maintaining a tree-form hydrangea requires annual pruning to encourage strong flowering. Unlike many flowering trees, panicle hydrangeas bloom on new wood, allowing for more aggressive pruning without sacrificing flowers. Prune in late winter before new growth begins, cutting back the previous year's growth by one-third to one-half.
This pruning stimulates vigorous new growth that will support large flower clusters. Remove any stems growing from the base of the plant to maintain the clean tree form. Panicle hydrangeas appreciate consistent moisture but tolerate some drought once established, making them relatively low-maintenance landscape trees.
8. Harry Lauder's Walking Stick (Corylus avellana 'Contorta')
This unusual contorted hazelnut creates one of the most distinctive small trees for garden focal points. The twisted, spiraling branches create fascinating shadows and silhouettes throughout the year. In late winter, pendant yellow catkins dangle from the bare branches like botanical ornaments.
When trained as a tree, this plant typically reaches 8-10 feet tall with a similar spread. The contorted branches become more pronounced with age, creating increasingly dramatic winter interest. Plant it where the unique branch structure can be highlighted against walls or sky backgrounds, especially when illuminated by low winter sunlight.
Growing Contorted Hazelnut Trees
Most contorted hazelnuts are grafted onto standard rootstock, which means they'll try to revert to the straight species form. Regularly check the base of the plant and immediately remove any straight shoots emerging from below the graft union. These straight suckers grow vigorously and can overtake the contorted form if left unchecked.
Contorted hazelnuts prefer full sun to part shade and well-drained soil. They develop the most interesting branch structure when grown in full sun. Little pruning is needed beyond removing dead or damaged branches and maintaining the clear trunk area. Their slow growth makes them suitable for smaller gardens where space is limited.
9. Smokebush (Cotinus coggygria)
Smokebush makes a striking specimen tree with its rounded form and unusual summer display. The name comes from the airy, smoke-like flower panicles that envelop the plant in summer, creating a misty, ethereal effect. Purple-leaved varieties like 'Royal Purple' add dramatic color contrast in the landscape.
As a tree form, smokebush typically reaches 10-15 feet tall with a similar spread. The multi-stemmed structure creates an interesting architectural element year-round. Position smokebush where afternoon sun will backlight the fluffy flower panicles, enhancing their dramatic effect against the colorful foliage.
Smokebush Pruning Options
Training smokebush as a tree involves selecting several strong stems to form the main structure and removing all others at ground level. Gradually remove lower branches to create a clear trunk area. Smokebush can be maintained with two different pruning approaches, depending on the desired effect.
For maximum "smoke" display, prune lightly in early spring, removing only dead or crossing branches. This preserves the flowering stems that produce the smoky effect. Alternatively, cut the entire plant back severely in early spring to encourage vibrant new foliage growth. This sacrifices most of the smoke display but produces larger, more colorful leaves, an especially effective technique for purple-leaved varieties.
10. Seven-Son Flower (Heptacodium miconioides)
Seven-son flower offers multi-season interest as a small tree for gardens. This uncommon plant produces clusters of fragrant white flowers in late summer when few trees are blooming. After the flowers fade, the bright red calyces remain, creating the illusion of a second flowering period in autumn.
When trained as a tree, seven-son flower reaches 15-20 feet tall with a vase-shaped canopy. The exfoliating bark peels to reveal a cinnamon-brown underbark that provides winter interest. This adaptable plant tolerates difficult conditions including urban pollution, making it suitable for challenging garden sites.
Seven-Son Flower Landscape Uses
Seven-son flower works beautifully as a specimen tree in smaller gardens or as part of mixed borders. Its late-season flowers provide valuable nectar for pollinators preparing for winter. The multi-season interest makes it a worthwhile investment for gardens where space is limited and plants must earn their keep with extended periods of ornamental value.
When selecting a planting location, consider the eventual height and spread. Seven-son flower grows relatively quickly, filling its space within a few years. Provide well-drained soil and full sun to part shade for best flowering. Minimal pruning is needed beyond establishing the initial tree form and occasional thinning of crowded branches.
11. Serviceberry (Amelanchier spp.)
Serviceberry naturally grows as a multi-stemmed large shrub or small tree, making it perfect for the "trub" category. This North American native offers four-season interest beginning with delicate white spring flowers that emerge before the leaves. Edible blue-black berries follow in early summer, attracting birds and providing sweet treats for gardeners.
As trees, serviceberries typically reach 15-25 feet tall with oval to rounded canopies. The smooth gray bark develops subtle striping with age. Fall foliage turns brilliant orange-red before dropping to reveal the elegant branch structure for winter interest. Plant serviceberries where birds can be observed enjoying the fruit.
Serviceberry Selection Tips
Several serviceberry species work well as garden trees. Allegheny serviceberry (Amelanchier laevis) and downy serviceberry (Amelanchier arborea) develop more tree-like forms naturally, while shadblow serviceberry (Amelanchier canadensis) tends toward a multi-stemmed habit that requires more training for tree form.
For smaller gardens, consider 'Autumn Brilliance' (Amelanchier × grandiflora 'Autumn Brilliance'), which reaches 15-20 feet tall with spectacular fall color. All serviceberries prefer moist, well-drained soil but adapt to various conditions once established. Their native heritage makes them excellent choices for supporting local wildlife.
12. Rhododendron (Rhododendron spp.)
Large-growing rhododendron species develop into magnificent small trees with patient training. Their evergreen foliage provides year-round structure, while the spectacular spring flower clusters create weeks of vibrant color. The leathery leaves often develop interesting textures and colors during winter months.
As trees, rhododendrons typically reach 12-15 feet tall with rounded, spreading canopies. The gnarled, twisting trunks develop character with age, especially in older specimens. Plant rhododendron trees where their shallow roots won't be disturbed and where they receive protection from harsh afternoon sun in hot climates.
Rhododendron Species for Tree Forms
Not all rhododendrons make good tree forms. Focus on larger species like Rhododendron catawbiense or Rhododendron maximum, which naturally develop more substantial trunks. Certain hybrid groups like the Dexter and Ironclad rhododendrons also reach tree-like proportions with age.
Train rhododendrons by gradually removing lower branches to reveal the trunk structure. This process should happen slowly over several years to avoid stressing the plant. Minimal pruning is needed beyond removing dead flowers and occasional thinning of crowded branches. Mulch well to protect the shallow roots and maintain consistent soil moisture.
Tree Form Gardening Success
Growing shrubs as trees opens up new design possibilities for gardens of all sizes. These versatile plants offer the structure and presence of trees without the overwhelming scale that full-sized trees can bring to smaller spaces. Their multi-season interest makes them valuable additions to landscapes where every plant must earn its keep.
The key to success lies in selecting appropriate species and providing patient training during the early years. Many garden centers now offer pre-trained tree forms, which provide instant impact without the waiting period. But there's special satisfaction in transforming a humble shrub into a garden centerpiece through thoughtful pruning and care over time.