Grapevine Bleeding: A Natural Phenomenon
What is Grapevine Bleeding?
Grapevine bleeding is a natural process that occurs when grapevines are pruned during their active growth period, usually in early spring. As the soil warms up and root growth surges, water is drawn up through the xylem, which is the woody tissue that transports water and nutrients from the roots to the leaves. If the vine is pruned at this time, the water pressure can cause sap to ooze from the cut surfaces.
Why Does Grapevine Bleeding Happen?
Grapevine bleeding occurs when the water pressure in the xylem exceeds the ability of the newly cut surfaces to seal themselves off with callus tissue. This can happen when the vine is pruned too heavily or when the soil is very wet.
Is Grapevine Bleeding Harmful?
Grapevine bleeding is not typically harmful to the vine, but it can lead to some problems. If the bleeding is excessive, it can drown out new buds or graft sites. It can also weaken the vine and make it more susceptible to frost damage.
How to Prevent Grapevine Bleeding
There are a few things you can do to prevent grapevine bleeding:
- Prune your grapevines at the right time. The best time to prune is in late winter or early spring, before the vines start to bleed.
- Avoid pruning too heavily. Only remove the necessary branches and canes.
- If you must prune during the active growth period, make sure to seal the cut surfaces with a pruning sealant.
- Water your grapevines deeply before pruning. This will help to reduce the water pressure in the xylem.
How to Treat Grapevine Bleeding
If your grapevines are bleeding, there are a few things you can do to stop it:
- Cut the wood at a slight angle to create an area where the water can run between the buds below.
- Cut at the base of the vine on either side to divert the bleeding from the graft site to the trunk base.
- Bend long canes slightly downward to ease draining.
The Benefits of Grapevine Bleeding
While grapevine bleeding can be a nuisance, it can also have some benefits. The sap that oozes from the cut surfaces contains important minerals and sugars that are vital to the vine’s frost protection. So, if the vine loses this frost protection, it could be at risk in the advent of further frosts.
Conclusion
Grapevine bleeding is a natural process that can be prevented and treated with proper care. By following the tips in this article, you can help your grapevines stay healthy and productive.
Additional Information
- Grapevine bleeding is also known as “crying vines” or “bleeding sap.”
- The sap that oozes from grapevines is not harmful to humans or animals.
- Grapevine bleeding can occur on any type of grapevine, but it is most common on vigorous vines that are pruned heavily.
- If you are concerned about grapevine bleeding, you should consult with a qualified arborist or viticulturist.
