oak leaf hydrangeas are not blooming

15 years ago

My 2 oak leaf hydrangeas did not bloom this year. The hydrangea pg's are doing wonderfully.....thanks to hard pruning by the deer over the winter....I did not know that they needed pruning to encourage new growth. We had a wet spring....the oak leaf's seem to be green and growing, but no flowers. Any suggestions?

Featured Answer

luis_pr

12 years ago

If they grow in dense shade, they will bloom poorly.

If they get too much fertilizer, they will stay nice & green but will not bloom so, make sure that you do not over do fertilizer applications. Note: fertilizer drift from the lawn can cause this problem; lawn fertilizer has a lot of nitrogen. There is low priced soil kit that can be bought to determine if your soil has too much nitrogen but I have not seen it for sale everywhere, only in selected nurseries.

A single fertilizer application in June (for the whole year) is enough if you live in the northern half of the country... twice a year if you live in the southern half (fertilize in May/June and again in July). The only exception is for potted plants. And you can add weak fertilizers during the growing season as long as you quit around July-August; this prevents the plant from forcing new growth just as winter arrives and kills all tender new growth.

Make sure that the plant does not get too little moisture or it will abort flower buds. It is drought tolerant but only up to a point. If your winter months are dry and the ground does not freeze, water every two weeks or so. Consistently moist soil should be the goal. For example: no dry periods, followed by wet periods, by dry, etc.

If you water too much, the plant can also develop root rot. Root rot prevents the top growth from getting enough water and the plant behaves as if you had not given it enough water. If root rot progresses, the plant leaves may brown out and the whole shrub could die.

Pests can also eat the flower buds: squirrels, deer, rabbits are hydrangoholics.

Oakleafs are hardy to Zone 5 so it would be rare for the weather to be a causal agent if you live in Zones 7-8.

Pruning at the wrong time can also cause this problem. Oakleafs begin flower bud production for Spring 2012 in July-August 2011. If you prune now then you would be cutting off next year's blooms. Similarly, if LAST YEAR you pruned on or after July, you may have cut off this year's blooms. The solution is to prune after the plant blooms but before the start of July.

Luis

Comments (6)

luis_pr
15 years ago
Are you suggesting that the deer might have nibbled on the oakleaf's flower bud and caused no blooms? Could happen. Oakleafs develop buds on old wood so the deer could cause problems if the nibble during winter. But pg's develop buds in spring on new wood so they would be ok.
trish_ns_z5
15 years ago
How old are they? Have they bloomed before? My oakleaf finally bloomed this summer - I've had her for 3 years. Don't know if it took her that long to get settled or if it was an easy winter. I've read that they do loose their flower buds if exposed to harsh winter winds/temperatures.
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nancy_groves_att_net
12 years ago
We planted several oakleaf hydrangeas in the spring of 2010 and had beautiful blooms. This year, nothing. The plants look healthy, but what happened to the flowers? Is there anything we can do to promote flowers next year and to ensure that several new oakleafs planted late last summer (they bloomed this spring) will rebloom?
madeyna
12 years ago
I would love to hear what it takes to get them to bloom as well. Mine has yet to blooom and I have had it 4 years. Its growing and healthy and in full sun.
goodhors
12 years ago
My dwarf Oakleaf took a couple years to settle in, though it did grow more stems without blooms in that time. Kind of "filled out" a little. Then about the third year it started blooming with a few flower heads and has improved every year since. It is about 9yrs old now.

Being dwarf it stays short, but is getting wider all the time, with many flowers each early summer.

Winter and cold, hard wind, doesn't seem to bother it much in the flower department. It is planted in an exposed location, and it can get quite cold some winters with a week or two of 10F or below. Not sure if wind chill does anything to the buds, because sometimes that drops to
-20F.

Probably some more time will help the Oakleaf most. Mine doesn't get much in special care, just mulching with real shredded Oak tree leaves. Still does well for me, so a good variety. While I enjoy the flower show, I love the huge leaves and appearance of the shrub itself.