Flowering dogwood trees are very popular with gardening enthusiasts. There are many varieties which display white or pink flowers, and the trees normally grow to about 30 feet in height when mature. However, dogwoods can also be temperamental and may not bloom if growing conditions are not to their liking. It usually takes several years before young dogwood trees begin to flower. If no flowers have appeared by the third or fourth year it usually indicates an environmental problem affecting the tree.
Ideal Growing Conditions
Dogwoods prefer partial sun which simulates their natural setting. In the forest, dogwoods are understory trees, a term which describes their position between the larger trees forming the canopy and the undergrowth below. This high humidity habitat provides only partial sunlight and an abundant supply of nutrients from the decaying humus on the forest floor. The ideal soil for dogwoods is well-drained and slightly acidic with a pH ranging from 5.2 to 6.0.
Many homeowners fertilize their lawns with high-nitrogen blends designed to encourage foliage growth. According to Beverly Shaw, advanced master gardener at Purdue University, nitrogen fertilizer applied around dogwoods increases the growth of leaves at the expense of flowers. Give your dogwood a wide berth when lawn fertilizing to make sure this is not a potential cause of non-flowering.
Providing a ring of mulch around the base of the dogwood is a good way to create favorable soil conditions. As in the forest, the decomposing mulch will add nutrients to the soil and make it slightly acidic. This technique works even better if lawn grasses are removed from around the tree so that the mulch is in direct contact with the topsoil. It is best to use mulch composed of leaves, needles and bark to simulate the forest setting as closely as possible.
Some trees may fail to produce flowers due to excessive light or poor soil conditions. Most yards and gardens don't have the large forest trees that would normally provide shade and protection to the dogwood. This can present a big problem if a tree is already well-established in a garden but has been planted in an open area. If moving the mature tree is not practical, planting new trees in partially shaded areas may be the only option.
Pruning out dead wood and trunk sprouts in the fall will make the tree more vibrant and encourage flowering. Check the trunk, branches and leaves for signs of infestation or disease. Although these conditions may not be directly related to the lack of flowers, the overall health of the tree must be maintained for flowering to occur. Keep lawn equipment, especially power trimmers and mowers, away from trees. The trunks can easily be damaged, which may make the tree an easier target for insects. Trunk cracks and scars can also make it difficult for the tree to get enough nutrients from the soil.