Question
QUESTION: Hi..I have 4 hydrangeas in each area and they are big and healthy but the blooms only open on the outside of the flower head. i know the variety opened fully when purchased so I am puzzled why only a few bud heads open and not the whole bloom !Does it need food/fertilizer/ or cutting back they are at least 1 cubic metre in size and very green and healthy looking and have grown tremendously well in this under window area getting full sun and loads of water! They have never been cut back and are a pink variety but were blue when i bought them!!

ANSWER: Hi Sara,
Thanx for your question.  I know you said you were from the UK but you didn't say exactly where.  That said, the bloom may be coming out on this year抯 green wood rather than last year抯 brown wood.  Current year blooms are always smaller and somewhat deformed. Next year will be better assuming no freezes.  If you had a late freeze this year that can adversely affect blooms.  This site has always helped me with hydrangeas.   http://www.hydrangeashydrangeas.com/

I hope this helps.
Tom

---------- FOLLOW-UP ----------

QUESTION: Thanks you for the answer, we are in middle England an hour north of London and YES we did have a very bad front in feb but it was over by march though it has been cold wet and a little ground frost up till April, the blooms are a bit deformed ! Should i cut the plant right back or give it a little prune and if so when should i cut them back. the flowers were all on new green shoots and appears healthy and prolific! Regards Sara

Answer
Hi Sara,
Thanx for your question.  I have been to your part of England before on a journey north to Edinborough back in the early 90s.  Beautiful country.  It sounds like you had some cold weather that probably adversely affected blooming.  We have a similar problem here in the U.S. in the north central part of the country where nurserymen sell varieties of hydrangea that are not reliably hardy to colder zones.  That means, the shrubery is fine and looks beautiful but the late cold, frost,etc. either kills or maims the blooming buds resulting in no flowering or in defromed or slight flowers.  You can dead head the plants if you like but hydrangea should seldom be pruned unless you are cleaning up diseased branches or the shrub has become totally unruly.  The more you prune, the more likely you will be removing growth that will set bloom next year.  I hope this helps.
Tom