Vibumum Chinese Snowball plants - Ask Extension
I purchased seven of these plants in May of 2022 and planted them (two at my mom's 35 miles away). Well care for--watered weeded mulched. lots of sun...
Knowledgebase
Vibumum Chinese Snowball plants #847457
Asked August 27, 2023, 9:20 AM EDT
I purchased seven of these plants in May of 2022 and planted them (two at my mom's 35 miles away). Well care for--watered weeded mulched. lots of sun. They have yet to bloom and this is year #2. The same situation at my mom's--great leaves (showing some stress from the heat last week.). Any ideas as to why they are not blooming? Do they need to be more established for that to happen? Just trying to find an answer to why they have no blooms. Great leaves--just no blooms.
Pottawattamie County Iowa
Expert Response
There are several reasons a shrub like this may not bloom. For your situation the most likely reason is maturity. Many shrubs often do not bloom for several (five or more) years after planting. The shrubs must grow and mature before they are capable of flowering. Selecting a favorable planting site and good cultural practices during establishment will encourage the shrub to flower as quickly as possible.
Another possible reason is pruning. Pruning at the right time is important as it can affect flowering. These shrubs bloom on the previous year’s growth. The best time to prune Chinese snowball viburnum is immediately after flowering in spring. Pruning these shrubs in late summer, fall, or winter may remove many (or all) of their flower buds. Also, protect the viburnum from browsing rabbits by placing wire fencing around the shrubs in fall. While you may not prune them, these animals can effectively prune for you damaging the shrub and removing flower buds.
Improper fertilization can also affect bloom. It is generally not necessary to fertilize blooming shrubs in Iowa. However, shrubs can be lightly fertilized in early spring. Heavy fertilization may promote excessive vegetative growth and discourage flowering.
Based on what you've mentioned, the other possible reasons are likely not the reason for the lack of blooms, but I'll mention them just to cover all the bases. Shrubs like this perform best in well-drained soils in full sun. Plants should receive at least six hours of direct sun each day. Viburnums planted in too much shade will not bloom well. Good care during the first two or three years is also important. Apply a 2- to 3-inch layer of mulch around each shrub to conserve soil moisture and control weeds. Water shrubs on a regular basis during dry weather. (which it sounds like you are doing).
Further questions can be directed to your local county Extension office. This local resource is very helpful since they are familiar with trends and issues in your part of the state. Click on this link to get connected directly with a staff person in your county Extension office and ask your gardening question. https://hortnews.extension.iastate.edu/ask-gardening-question
Happy gardening!
--Aaron
Another possible reason is pruning. Pruning at the right time is important as it can affect flowering. These shrubs bloom on the previous year’s growth. The best time to prune Chinese snowball viburnum is immediately after flowering in spring. Pruning these shrubs in late summer, fall, or winter may remove many (or all) of their flower buds. Also, protect the viburnum from browsing rabbits by placing wire fencing around the shrubs in fall. While you may not prune them, these animals can effectively prune for you damaging the shrub and removing flower buds.
Improper fertilization can also affect bloom. It is generally not necessary to fertilize blooming shrubs in Iowa. However, shrubs can be lightly fertilized in early spring. Heavy fertilization may promote excessive vegetative growth and discourage flowering.
Based on what you've mentioned, the other possible reasons are likely not the reason for the lack of blooms, but I'll mention them just to cover all the bases. Shrubs like this perform best in well-drained soils in full sun. Plants should receive at least six hours of direct sun each day. Viburnums planted in too much shade will not bloom well. Good care during the first two or three years is also important. Apply a 2- to 3-inch layer of mulch around each shrub to conserve soil moisture and control weeds. Water shrubs on a regular basis during dry weather. (which it sounds like you are doing).
Further questions can be directed to your local county Extension office. This local resource is very helpful since they are familiar with trends and issues in your part of the state. Click on this link to get connected directly with a staff person in your county Extension office and ask your gardening question. https://hortnews.extension.iastate.edu/ask-gardening-question
Happy gardening!
--Aaron
