Dogwood trees (Cornus species) are one of South Carolina’s beautiful flowering tree species, blooming in early spring. Their white flowers can often be seen in the forest understory before most other trees have leafed out, and many people have them as a part of their landscape. But, sometimes, that dogwood in your yard might not bloom like you expected, or it might not leaf out as normal. So why is this happening? There are several reasons, so let’s take a look at them.
Typically, when any tree doesn’t leaf out or flower normally, it’s a sign of stress. With few exceptions (which we’ll discuss later) most of the time, dogwoods that don’t leaf out or flower are simply stressed. Proper tree maintenance can often alleviate stress.
It is important to remember dogwoods naturally grow on forest edges or in areas where they get some shade and some sun. A dogwood tree planted in the middle of a yard or in full shade is not getting the environmental conditions that this species is used to getting. This in and of itself can stress the tree. And on that note, dogwood trees planted in the middle of a yard receive whatever inputs are applied to the yard. This typically means fertilizers that are high in nitrogen. Nitrogen helps plants make green tissue (i.e., leaves – this is why some lawns are so green, because they receive a lot of fertilizer that’s high in nitrogen content). Now while this fertilizer is great for lawns – and will promote tree growth – it will promote leaf growth, not flower development. In some cases, flowering trees don’t flower simply because they’re getting too much nitrogen.
Another reason a dogwood tree might not leaf out or flower normally is because it’s getting too much or too little water. Dogwoods grow on well drained sites in nature, so if your tree is in a low area of your yard, for example, it might be getting a lot more moisture than the tree is used to. Some trees don’t like “wet feet” (post oak is a great example of this) and almost all trees are negatively impacted by drought, so anytime water conditions aren’t right you’re likely to see impacts. Likewise, temperature matters – dogwoods surrounded by structures, concrete, or a paved driveway will experience warmer temperatures than those surrounded by other plants simply because the heat will be reflected off these impervious surfaces. This too can impact leaf out and flowering.
Sometimes, none of those things appear to be “off”, and it can be difficult to determine what exactly is stressing the tree. In these cases, it’s worth thinking about how the tree was planted. Was it planted too deep (i.e., can you see the root flare)? Are there girdling roots wrapped around the trunk, cutting off the tree’s ability to obtain water and nutrients? Many times impacts from improper planting aren’t seen until years later, and can be difficult to identify.
Also, it’s important to remember that for trees that flower early in the spring (like dogwoods), flower buds are formed during the previous summer and fall. So, if you prune in late fall or winter, you are removing next spring’s flower buds.
And let’s not forget about pests. The main pest of dogwoods is a disease called dogwood anthracnose. This fungus (Discula destructiva) starts out as leaf spots, but soon spreads down the branches into the main stem, causing dark lesions (cankers) where the branch meets the trunk. These cankers can kill the branches and girdle the tree, resulting in a tree with many epicormic branches. Eventually, infection from dogwood anthracnose can kill the tree. Fungicides can be used to manage the disease, as well as certain cultural treatments. Planting resistant dogwood varieties (like Kousa dogwood, Cornus kousa) is also an option.
So, the answer to the question “why isn’t my dogwood tree blooming or leafing out?” isn’t so simple. Many different factors can impact tree health, which in turn impacts leaf out and blooms. If you have a dogwood tree that is late to leaf out or bloom, be sure to give it a thorough check for these things or call your local Clemson Extension professional.
For even more information, check out our HGIC factsheets relating to dogwoods and tree care:
Dogwood- https://hgic.clemson.edu/factsheet/dogwood/
Dogwood diseases, insects and pests- https://hgic.clemson.edu/factsheet/dogwood-diseases-insect-pests/
Tree Maintenance- https://hgic.clemson.edu/factsheet/tree-maintenance/
Planting trees correctly- https://hgic.clemson.edu/factsheet/planting-trees-correctly/
Author
Dave Coyle, Cooperative Extension, Forestry and Wildlife Specialist
Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, gender, religion, national origin, disability, political beliefs, sexual orientation, gender identity, marital or family status and is an equal opportunity employer.
