Many gardeners notice that some trees and shrubs leaf out later than others in spring. This can raise concerns about plant health, especially after a harsh winter or late frost. In many cases, delayed leaf emergence is normal. In other situations, it can signal environmental stress or injury.
Causes | What To Do | When to Be Concerned | Trees & Shrub Species with Late Leaf Out | Late Emerging Perennials | More Information
Common Causes of Late Leaf Emergence
Several factors can influence when trees and shrubs break dormancy and produce leaves.
Species Characteristics
Some species naturally leaf out later than others. These plants require more accumulated heat before growth begins. Late leafing is often an adaptation that helps avoid damage from spring frost.
Cool Temperatures
Cool spring temperatures slow the accumulation of growing degree days, delaying bud break. A prolonged cool period can make all plants appear behind schedule.
Late Frost
If temperatures fluctuate widely in spring, producing a warmer period that promotes growth followed by below-freezing temperatures, newly emerged buds or small leaves are damaged. In response to late spring frosts, plants may produce new leaves from secondary buds, which takes additional time.
Winter Injury
Severe winter temperatures, rapid temperature fluctuations, or desiccation can injure buds and cambium tissue. Damaged buds may fail to open, forcing the plant to rely on secondary or latent buds, resulting in delayed leafing.
Spring Foliar Diseases
In some cases, leaves emerge late because early foliage was damaged by disease. Anthracnose is a common example on sycamore, as well as on ash, oak, and maple. During cool, wet springs, infected leaves may drop soon after they emerge. The tree then produces a second flush of leaves from secondary buds, which delays full canopy development.
Drought Stress
Dry conditions in the previous growing season can reduce carbohydrate reserves. Plants with limited energy reserves may leaf out slowly or unevenly.
Root Stress or Damage
Compacted soil, poor drainage, or root injury from construction or transplanting can delay growth. Roots must function properly before shoots can develop.
Transplant Shock
Recently planted trees and shrubs often leaf out later than established plants. This delay reflects the plant’s effort to reestablish roots.
What Gardeners Should Do
A wait-and-see approach is often appropriate early in the season. Many plants will leaf out once sufficient heat accumulates.
Be Patient
Compare the plant to others of the same species in your area. If they are also delayed, the cause is likely environmental rather than plant health.
Perform a Scratch Test
Gently scratch the bark on small twigs. Green tissue beneath the bark indicates the branch is still alive. Brown, dry tissue suggests dieback.
Prune Dead Wood
Once new growth begins, prune out dead branches. This improves appearance.
Provide Proper Care
Support plant recovery with good cultural practices:
- Water during dry periods
- Apply mulch to conserve soil moisture
- Avoid excessive fertilization, which can stress weakened plants
Avoid Premature Removal
Do not remove a tree or shrub too quickly. Some species are naturally slow to leaf out and may appear dead well into spring. Wait until at least June 1st before making any determination about the survival of a tree or shrub that has not yet leafed out.
When to Be Concerned
Late leaf emergence is typically a product of the weather and plant species. However, other factors such as winter dieback, drought stress, root damage, or transplant shock, may be responsible for the problem when:
- No bud swelling is evident well into the growing season (after June 1st)
- Branches fail the scratch test
- Only portions of the canopy leaf out
- There are signs of bark splitting or discoloration
In these cases, actions to provide proper care (watering, mulching, etc.) should be taken to help remedy the problem.
Common Trees and Shrubs with Late Emerging Foliage
The following species often leaf out later than many other landscape plants. These species typically require greater heat accumulation before breaking dormancy and may not leaf out until late spring.
Shade Trees
- Black walnut (Juglans nigra)
- Honeylocust (Gleditsia triacanthos)
- Kentucky coffeetree (Gymnocladus dioicus)
- Northern catalpa (Catalpa speciosa)
- Sycamore (Platanus occidentalis), especially in wet spring when anthracnose is prevalent
- Hickory (Carya spp.)
- Pecan (Carya illinoinensis)
- Some peach and apricot cultivars, particularly after cold springs
Shrubs
- Rose of Sharon (Hibiscus syriacus)
- Bluebeard (Caryopteris spp.)
- Butterfly bush (Buddleia spp.)
- Buttonbush (Cephalanthus occidentalis)
- Panicle hydrangea (Hydrangea paniculata)
- St. John’s wort (Hypericum spp.)
- Beautyberry (Callicarpa spp.)
- Smoke tree (Cotinus coggygria)
- Devil’s walkingstick (Aralia spinosa)
Vines
- Trumpet vine (Campsis radicans)
- Hardy kiwi (Actinidia arguta)
- Grapes (Vitis spp.), especially in cool springs
Late Emerging Perennials
Woody plants are not the only plants in the garden to get a late start. Learn more about late emerging perennials in this article: Late-Emerging Perennials: Some Species Just Get a Late Start to Spring!
Further Reading
- Some species of trees green-up earlier than others Michigan State University
More Information
- Cold and Freeze Damage to Garden Plants
- Will freezing temperatures harm fruit trees that have leafed out?
- Browning and Dieback on Conifers
Photo credits: 1: University of Maine; 2: Varga_photography AdobeStock; 3: Aaron Steil; 4: Aaron Steil; 5: Aaron Steil