Sun or Shade for Hydrangea?

[dcamp1017]

I have a hydrangea planted in a spot that is mostly shaded all day. While it looks healthy (beautiful green leaves) it has not bloomed in 5 years.

I would like to transplant it this fall to a location that gets full sun. Can hydrangeas take full sun all day?

Thank you.

[luis_pr]

It depends. In the souther states, the leaves scorch if allowed exposure to the Sun after 11am or 12pm during the Summer. I let my hydrangeas get sun from 7am-11am/ish. As you travel further north, they can handle more sun, to the point where they can grow in full sun near the Canadian Border. Experiment by moving the shrub to various locations and move it to a more protected location if the leaves turn white-ish or completely yellow (including the leaf veins). One caveat: make sure that this variety can grow outside in your zone!

I am surprised you have not gotten blooms though. Do you prune this shrub? If it is a hydrangea variety that blooms on old wood, do not prune on or after July; instead, prune after blooming but before July. Try to maintain the soil moist as evenly as possible. Dry cycles can cause the plant to abort flower buds. Provide water during winter (but not as often; maybe weekly or every two weeks). Place the pot in a garage or shed to get protection from the worst of winter. Allow it to get 2-3 hours of sun. Add mulch so you do not have to water too often this time of the year. Fertilize the soil often with a slow-release fertilize (NPK 10-10-10 or an approximate multiple thereof) since all the constant watering causes many of the nutrients to leech out through the holes in the bottom of the pot.

[rainbowgardener]

luis is extremely knowledgeable about hydrangeas, but he assumed yours is in a pot/container. The way you talked about transplanting, I didn't read it that way. Is your hydrangea planted in a lawn? Do you fertilize your lawn? One of the (other) things that can cause the hydrangea to thrive but not bloom is lawn fertilizer which is high nitrogen. For lawns you want lots of leaves (grass blades) and not flowering, but if the hydrangea is sitting in the middle of it, or receiving run off from it, you can get the same effect on the hydrangea.

[luis_pr]

Good catch. Dcamp1017, you said the shrub was planted in a "spot" and I read "pot" instead. Ha! Sorry about that! Concentrate on these possible causes for the lack of blooms:

make sure that this variety is hardy in your zone; if not you will need to winter protect it. Do you prune this shrub? If it is a hydrangea variety that blooms on old wood, do not prune on or after July; instead, prune after blooming but before July. Try to maintain the soil moist as evenly as possible. Dry cycles can cause the plant to abort flower buds. Provide water during winter (but not as often; maybe weekly or every two weeks). Allow it to get at least 2-3 hours of sun. Add mulch so you do not have to water too often this time of the year. Fertilize the soil only once, in June, using either aged manure, compost or cottonseed meal. You can also use a general purpose, slow-release fertilizer with a NPK Ratio of around 10-10-10. If you transplant it, do it when the shrub has gone dormant in mid-late Fall or Winter.

[microcollie]

Provide water during winter (but not as often; maybe weekly or every two weeks). Allow it to get at least 2-3 hours of sun. Add mulch so you do not have to water too often this time of the year.

I'm not sure what part of Ohio we're talking about, but it's probably an area where the ground freezes hard for most of the winter. If I did that here in my zone 4 garden, plants would heave and/or suffer root damage from the freeze/thaw cycles. I leave my hydrangeas alone until they break dormancy in the spring.