Hydrangeas are one of the most popular shrubs around. Highly prized for their large soft-colored or white flowers, hydrangeas provide an attractive flower display both on the shrub and as part of cut flower arrangements.  The subject of much garden research (soil pH, pruning and blooming) these showy flower displays are worth all the effort. So, if hydrangeas aren’t providing you with the blooms you want, it’s time to find out why.  Below are some tips to encourage your hydrangeas to give you maximum bloom capacity.

Sun

Grow hydrangeas in as much sun as the plant will tolerate for more blooms. In Connecticut, most hydrangeas can take full day sun. Sunlight is the number one key to getting a bounty of blooms on your hydrangeas, so never grow them in full or heavy shade.

Water

Hydrangeas like a fair amount of water.  After all, their name comes from the Greek word “Hydros,” meaning water.  Your hydrangeas should get a minimum of 1” of water every week.

During the height of summer and really hot, water twice a week. The best time of day is early morning before the day gets hot and the water evaporates. Water slowly and deeply, so they have a chance to really absorb the water into their root system. If they become stressed because of lack of water (drought stressed), the first signs they will exhibit is lack of flower production. Flower production requires a lot of energy and energy requires water.

However, don’t over water. Signs of over watering include yellowing or wilting. Yes, I know, these are similar signs to drought stress. A good idea is to get a soil moisture meter, which will tell you the moisture that’s in the ground. This takes the guess work right out of it. A hydrangea will droop or wilt when it’s thirsty (as will all plants), but they recover quickly after watering.

Fertilize 

Apply a 10-10-10 slow-release fertilizer early in the spring before the hydrangea starts to leaf out. Be sure to work it into the soil and water well. I prefer an all natural, organic fertilizer. Repeat the application after the bloom season ends.  

Mulch 

Apply a 3” layer of mulch all around the shrub’s dripline (the outer edge of the branches) in the spring. Be careful to leave an inch or so around the base of the plant. Mounded mulch can cause rot and insect damage. 

Deadhead 

Deadhead the hydrangeas throughout the season to encourage more blooms just as you would any other flower. Use sharp pruning shears and cut at a 45° angle being careful not to crush the stems. Prune dead flowers back to the main stem. Flowers that are left after they’re done blooming will dry and attempt to go to seed, thus ending the flowering cycle.

Pruning 

Here’s the tricky part, some hydrangeas bloom on old wood (many macrophylla varieties) and need to be carefully pruned. Prune out the dead and never prune any living branches later than late summer. Prune hydrangeas that bloom on current year’s wood (Arborescens varieties) in early spring before the shrub produces new growth. Hydranges pruned back to 2” to 3” produce more blooms than those that aren’t pruned. 

Click to read Sandi’s last post: “Selecting Plants for Your Garden”