Hydreangeas

Glenjjones

Hi,

I hope one of you lovely people might be able to help me. I have 2 hydrangeas in my garden, and I find that though they come back each year they don't seem to be growing much bigger, and they don't flower that well.

I don't really do much to them, and I was wondering if you had any advice for making them grow larger and also flower stronger.

I'm guessing increasing watering and feeding would be a good start, but any other thoughts are very welcome.

K67

What type are they?

Glenjjones

not sure? I think they are both Macrophylla.

one is a fairly standard green leaves and blue/pink balls of flower.
the other has very dark foliage and a pinky green flower that has the outer ones open and the inner ones closed.

I don't know if that helps but I don't know the exact varieties, as they were planted a few years ago, and I didn't bother noting them at the time.

rachelQrtJHBjb

Can you talk us through your pruning regime as this may be affecting growth and flowering. 

K67

I don't think you have a pruning regime so try this for advice
https://www.rhs.org.uk/plants/popular/hydrangea/shrubby/growing-guide

The flatter one is probably a lace cap type and the other is also called a mop head 

luis_pr

"they don't seem to be growing much bigger" - this comment suggests that the old stems from last year might be getting zapped/killed often. This can occur under various scenarios:

* if they get fertilized late in the growing season, an early frost can zap the stems so try not fertilize anymore -for example- after the end of June;

* winter is cold enough to kill the stems or a watering issue dries out the plant too much during winter;

* the plants break dormancy early but last year's stems then get zapped by a late frost so winter protect the plants or use hydrangea macrophyllas that bloom twice a year or switch to use a serrata (also called Mountain Hydrangea) as this type blooms late and might 'escape' late frosts, a Annabelle-like hydrangea arborescens varieties or Pee Gee-like hydrangea paniculata varieties.

With your plants growing from the crown every year, there is no chance to get an increase in size. Arborescens and paniculatas are more winter hardy. They bloom on new wood and begin to produce flower buds in late Spring or early Summer.

"they do not flower that well" - cold temperatures (early frosts, winter cold, late frosts) can kill flower buds on any left over stems from last year that do make it. A macrophylla that blooms twice may be useful. They will bloom on old wood and new wood so you get the usual Spring blooms and then new ones around the summer months. Arborescens and paniculatas are more bloom reliable as they begin producing flower buds in late Spring, when late frosts are unusual.

"I don't really do much to them" - hydrangea macrophyllas will develop new flower buds for Spring several months after they bloom. So, be careful with the pruning regime, if you do any pruning. Pruning soon after they originally bloom will prevent you from cutting next year's flower buds. These invisible flower buds are located near the ends of the stems but are inside the stem until they finally open in Spring. If the hydrangea was planted in a location where it can achieve its plant label's estimated size at maturity, there should be little pruning needed: just remove dead stems leftover from harsh winters and deadhead any spent blooms (I just let the spent blooms fall on their own).

"any other thoughts" -

To know when to water: insert a finger into the soil to a depth of 10cms and water if the soil feels dry. Skip watering if the soil feels soggy but consider watering extra or manually if there is a wind advisory as windy conditions can help dry out the top of the soil where hydrangea roots normally are. Water early, like near sunrise, if you want in order for the leaves not to stay wet for long periods. Better yet, water only the soil and never the leaves to minimize the chances of fungal infections like leaf spots and powdery mildew. You can start watering the crown/base and then water outwards in all directions.

To know if you watered enough: water the soil and wait a while so the water is absorbed; insert a finger into the soil in several spots to a depth of 20cms; if the soil is dry, you may have missed a spot or you need to use more water. Once temperatures typically warm up in the summer months, be ready to increase the watering amounts from "Spring levels" to "Summer levels".

Maintain 5-10cms of organic mulch throughout the year. Maintain the soil as evenly moist as you can.

Good luck, Luis

Glenjjones

Thanks guys,

You are correct in the assumption that I have never pruned them. due to their small size I have never seen the need.

They don't die back to ground level, but the just don't seem to grow much each year. I see others that seem to put on 12 inches plus growth in a year, but mine struggles to put on 2 inches.

I'll try paying them more attention this year and feeding and watering more regularly, and no doubt I'll ask you lovely people again if I have any questions or problems.

luis_pr

I have a large specimen that came with my home. It must more than 20 years old but it too does not get large. Because my winters are mild sometimes, the stems get killed when the plant breaks dormancy early and a late frost/freeze follows. The plant then starts growing from the crown/base and it gives itself a "hair cut" every few years. That helps keep its size in check in a way. But if this issue happens a lot, another type of hydrangea may work better there. A re-bloomer macrophylla, an Annabelle-like smooth hydrangea or a paniculata. Maybe a compact oakleaf hydrangea as they have nice Fall foliage too.