How to Identify a Spring Purple Flowering Tree

If you've ever admired a lovely lavender-hued tree in the springtime and wondered how to find out what it is, there are a few steps to help identify that purple spring bloomer. You'll need to spend a little time familiarizing yourself with botanical terms used to describe the tree and its parts, including the leaves and flowers. The shape of a tree and where it grows are also key elements in determining the exact species you're researching. We'll use a well-known spring bloomer to help guide us: the common lilac, Syringa vulgaris.

Things You'll Need

• Tree leaf or blossom
• Tree identification guide

Instructions

Look Closely at the Parts

1. The most important factor in figuring out the kind of tree you're looking at is to determine whether it is deciduous or coniferous. Most deciduous trees lose their leaves each autumn, though there are exceptions to this rule, such as some rhododendrons and oak trees. Conifers are generally defined as evergreen trees which produce seeds enclosed in a cone. Examples include fir, spruce and cedar.

   The lilac is deciduous, since it loses its leaves each fall.

2. Most trees' leaves are arranged oppositely or alternately. Just as it sounds, opposite leaves grow directly across from one another on the branch. Leaves arranged alternately grow stepwise along the branch, one above the next.

   To the layperson, a leaf is just a leaf. But to the botanist, leaves are either simple or compound. Simple leaves grow directly from the twig. Compound leaves have three or more leaflets growing from a central midrib, or rachis.

   Leaf margins are also important in identifying the tree. Margins can be smooth and unridged, or "entire"; ridged or "serrate"; or with protrusions, termed as "lobed."

   The lilac's leaves are opposite and simple, with entire margins.

3. If, after you've cross-referenced your leaf sample with a comprehensive tree guide and are still coming up empty, it's time to take a closer look at the flower, called the inflorescence. Note the color, and whether or not it has an aroma. Check to see if the flowers are growing singly or in clusters.

   The lilac has fragrant flowers ranging in color from purple to white, arranged in long sprays called panicles.

4. Many flowering trees can be identified based on the month their blooms appear. For instance, the lilac shrub tends to bloom in May. Another notorious purple spring bloomer, the redbud tree, flowers in mid-April.

5. A final aid in determining the type of tree is to note its shape and growth habit, or form. Walk several yards from your target tree and assess its overall shape.

   Is the tree tall---over 16 feet---or short? Does it have a single dominant trunk, or several smaller stems? Does it grow straight with a full crown, or do the limbs spread wide to form a broad crown? Is it growing in full sun, part sun, or in shade?

Tips & Warnings

• A majority of spring flowering trees are pink or white, so a purple flower helps narrow the field of candidates considerably. If you're stumped, try researching this list of spring bloomers, all of which have purple-colored flowers, to see if any match your mystery tree.

• Buddleia -- Butterfly Bush

• Catalpa speciosa -- Catalpa

• Cercis canadensis -- Redbud

• Cotinus obovatus -- American Smoke Tree

• Hibiscus syriacus -- Rose of Sharon

• Hydrangea macrophylla -- Bigleaf Hydrangea

• Jacaranda mimosifolia -- Jacaranda

• Rhododendron catawbiense -- Rhododendron 'Catawba'

• Syringa vulgaris -- Common Lilac

• Tibouchina granulosa -- Purple Spray Tree or Glory Tree

• Daphne odora -- Daphne

References

• North Dakota State University: Common Lilac
• Dendrology at Virginia Tech: ID It
• Dendrology at Virginia Tech: Basics of Tree ID

Resources

• GardenPilot: Growing Purple Flowering Shrubs
• USDA Plants Database: Syringa Vulgaris