Blooming Deciduous Trees and Shrubs: A Toronto Master Gardeners Guide

 

Flowering dogwood (Cornus florida) is very showy in spring. (Photo: Helen Battersby)

Deciduous trees and shrubs are plants that lose their leaves in the fall. Trees are generally single stemmed while shrubs tend to be multi-stemmed plants. In the fall, the leaves of some trees and shrubs change colour to vibrant hues of red, yellow or orange before losing them altogether. The intensity of the fall colour will often depend on the growing conditions of the season.

Most trees and shrubs bloom in the spring before their leaves emerge. As always, there are exceptions. For example, Buddleia davidii (Butterfly Bush) blooms in mid-summer while Hibiscus syriacus (Rose of Sharon), and Caryopteris clandonensis (Blue Mist Shrub) bloom in late summer.

Both trees and shrubs provide visually pleasing colourful flowers, scent, contrast, vertical and horizontal height and form to the landscape. As an added bonus, many blooming trees and shrubs produce colourful fruit or berries in the fall, attracting wildlife and extending their interest into the winter.

Choosing The Right Blooming Tree Or Shrub

Location in the Garden

A strategically placed flowering tree or shrub can be used as a focal point in the garden. Tiered plantings are also an option, with taller growing material planted toward the back of the garden and shorter material in front. This arrangement will allow all of the plants to be seen.

Flowering ornamental fruit trees may be outstanding in the spring. However, bear in mind the possibility of messy fallen fruit that may come later in the summer or fall. Avoid planting them near walkways or driveways.

When planting, the size at maturity (height x width) should also be taken into consideration. Is there plenty of growing space away from buildings and overhead wires?

‘Maiden’s Blush’ lilac (Syringa hyacinthiflora ‘Maiden’s Blush’) is a very fragrant cultivar. (Photo: Helen Battersby)

Hardiness Zone

Hardiness zones are another very important consideration when selecting flowering shrubs or trees. Make sure the tree or shrub you are considering will survive in your area. Check the tag when purchasing as it will tell you the minimum winter temperature the plant can tolerate.

Lighting

Lighting is important to consider when choosing a flowering tree or shrub. For your new plant to thrive, it must have the right amount of light. Six plus hours is deemed full sun, whether it’s direct late-morning or afternoon sun. Four to six hours is considered partial sun and less than four hours is considered full shade (no direct sun but in a bright location). The tag on your new plant will have an icon representing the plant’s light requirements. If it says full sun and your garden is shady, don’t buy it!

Soil Type

Is the soil acidic or alkaline? It may be necessary to do a soil analysis to determine whether your soil is suited to the tree or shrub you have chosen. Amendments may be necessary in order to be sure your new plant will thrive in your garden. Also check to see whether your soil is clay, loam or sandy. This may also affect the ability for your plant to bloom and thrive. Ultimately, the best approach is to choose the right plant for the right location to ensure its health and vigor.

The flowering crabapple (Malus spp.) comes in colours, white through deep pink. (Photo: Helen Battersby)

Maintenance

Shrubs and trees will require little maintenance if they are sited and planted properly with the required nutrients. They must be watered regularly until established and also in times of drought. Make sure you use the original soil and top dress every spring with good compost, well-rotted manure, or quality organic fertilizer.

Pruning

Pruning is a method of controlling growth, shape and enhancing the quality or quantity of flowers and fruit on trees and shrubs.

Always use sharp tools and sterilize the tools with a mixture of 1 part bleach to 10 parts water after each cut to prevent the spread of disease. Remove branches that are dead, diseased, or damaged. Try to remove the pruned material out through the crown, do not drag the material through the branches. Dragging diseased branches through the crown can spread the disease through the tree. You may also want to consider removing branches that do not go with the character of the tree or shrub.

Thinning out branches by pruning should also be considered as it improves air circulation which helps to prevent mould. Thinning also increases light penetration to the center of the tree or shrub, thus improving photosynthesis.

It is important to know when to prune your flowering trees and shrubs. Some trees and shrubs flower on the current year’s wood and others bloom on last year’s wood. If you prune them at the wrong time, you may eliminate flower buds and end up with a poor show.

Some examples of shrubs that flower on the current year’s wood are: Hydrangea quercifolia (Oakleaf Hydrangea), Berberis thunbergii (Barberry) and Weigela florida (Weigelas). Generally, shrubs in this category are pruned in the spring. Shrubs that flower on last years wood are : Syringa vulgaris (Lilac), Forsythia, Deutzia gracilis (Deutzia), and Philadelphus viginalis (Mock orange). Generally, shrubs in this category are pruned directly after the blooms have faded and before next year’s buds have formed.

Suggested Blooming Trees And Shrubs

Laburnum gets its common name golden chain tree for obvious reasons. Take care, as all parts of the plant, especially the seeds, are poison. (Photo: Helen Battersby)

Trees

Malus x robusta – Cherry Crabapple

Cornus florida – Dogwood

Laburnum anagyroides – Golden Chain tree

Magnolia macrophylla – Magnolia

Hibiscus syriacus – Rose of Sharon

Liriodendron – Tulip Tree

Shrubs

Azalea – Azalea

Kolkwitzia – Beauty Bush

Callicarpa – Beauty Berry

Hydrangea macrophylla – Bigleaf Hydrangea

Caryopteris clandonensis – Blue Mist Shrub

Spirea prunifolia – Bridal Wreath Spirea

Daphne x burkwoodii – Burkwood Daphne

Buddleia – Butterfly Bush

Viburnum trilobum – Cranberry Bush

Potentilla – Cinquefoil

Syringa vulgaris – Common Lilac

Fothergilla gardenii – Dwarf Fothergilla

Sambucus canadensis – Elderberry

Forsythia – Forsythia

Blooms of the hybrid form of witch hazel (Hamamelis x intermedia) are welcome in spring. (Photo: Helen Battersby)

Hamamelis x intermedia – Hybrid Witch Hazel

Philadelphus – Mock Orange

Physocarpus – Ninebark

Hydrangea quercifolia – Oak-Leaf Hydrangea

Salix – Pussy Willow

Hibiscus syriacus – Rose-of Sharon

Clethra alnifolia – Summer- Sweet

Weigela florida – Weigela

References

Thomas, William, ed. Hearst Garden Guides. Trees and Shrubs. New York : Hearst Books, 1992.

Hyland, Bob. Brooklyn Botanic Garden, Shrubs, The New Glamour Plants. New York: 1994

Date revised: January 30, 2011

For printable version, click: Blooming Deciduous Trees and Shrubs – A Toronto Master Gardeners Guide 

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