Why Isn't My Hydrangea Blooming?

Why isn't my hydrangea blooming?

One of the most popular plants I sell are hydrangeas. From small to large blossoms of white, red, pink, blue, purple, bi-color and the list just seems to get expanded more and more each year.

When you break down the name, hydrangea, the Latin "hydra" translates into water. These plants do like moist areas but have been known to grow in dry well draining soils as well.

First, let's break down the types of hydrangeas....

#1 Hydrangea macrophylla- These are rounded "snowball " like flowers that prefer part sun to a shaded situation. Some are remontant, or repeat bloomers while others seem to be quite finicky and bloom when they feel like it.

I am often asked why my hydrangea is not blooming. Improper timing of trimming on these varieties are the main culprit. The rounded macrophylla varieties of hydrangeas should only be pruned in mid to the end of August when flowers are at the end of their bloom cycle. They will start setting flower buds late August and into September for the next year. Improper timing of pruning could cause flower buds to be trimmed off. Late frosts or snows like we had in previous years caused a lot of flower buds to be frozen and negated flowering for the year. 

Insufficient light is another possibility. Hydrangeas do like shade, but deep shade will not yield many, if any flowers. 

If you do have a hydrangea which seems stubborn and you have not pruned at the wrong time, I always suggest taking a sharp spade and digging on one side only the plant as if you were going to transplant it to a new location. This usually shocks the plant into blooming the next year. The stress to the plant causes it to go into survival mode and procreate with flowers. It's not 100% a cure but works a lot of the time. Also, a good shot of fertilizer like espoma's holly-tone will help with producing flowers as no plant will do well if it is starving.

Check the flow chart out by proven winners to see why your hydrangea may not be blooming.

The pH of your soil also has a lot to do with the color of your hydrangeas. If you add lime and raise the ph of soil, your flowers will be pink, the higher the ph, the pinker the flowers. Conversely, if you add aluminum sulphate or soil Sulphur and lower the ph, your flowers will be blue. The aluminum sulphate really gets flower colors almost an electric blue. I have some clients which experiment with varied combinations of lime and aluminum sulphate, one puts lime on the left side and aluminum sulphate on the right, this yields mixed colors on the same plant.

#1 Hydrangea macrophylla- Some of my favorite hydrangeas in the macrophylla varieties are endless summer varieties as well as forever and ever varieties. These re-bloomers come in all colors and bloom on new and old wood so the potential for flowers is greater year after year. My top three picks are, Endless summer's summer crush which starts out deep pink raspberry red and changes to purple, it's a great showstopper. Endless summer Bloomstruck is a vivid rose pink to purple bloomer. It has strong stems and supports the weight of its flowers on beautiful red purple stems. My 3rd favorite is Cherry Explosion which is a lacecap flower with cherry-pink blossoms with a paler pink center.  I also like "Tiny Tuff Stuff" which has a unique flower you have to see to believe. It is very hardy and blooms every year even in extremely cold winters and springs.

#2 Hydrangea paniculata- These cone-like flowers appear as early as June and flower through fall. Fun names like pinky winky, strawberry sundae, strawberry-vanilla, limelight and Bobo lead the best sellers list. Bobo is a small plant that blooms so much, all you see in flowers!

These cone shaped flowers should be pruned in spring before they leaf out. Thinning competing branches and removing dead blossoms will make these hydrangeas flower like crazy. Paniculata varieties like full sun but will grow in areas where they get 4-5 hours of good sun. The more the better.

Tree forms of these plants are available as well. A trained or grafted 30" standard elevates a standard bush form into a hydrangea with a trunk. These are great for focal points at edges of landscapes where some height is needed but a standard tree will get too big. 

Quick fire variety is the first to bloom in June. If you need a shorter version, try "Little Quick-fire". Pinky winky starts out white and fades to pink and then red as fall arrives. Limelight is lime green and almost seems to glow. It is a very unique color and is a head turner. "Limelight Prime" has been introduced as a smaller version of limelight and is a great plant.

#3Hydranges quercifolia-These are known as oak leaf hydrangeas. Leaves are serrated like oak tree leaves and thus, this is where they get there name. These should be trimmed in early spring as well.

One unique variety is ruby slippers, which has a unique blossom which starts out white and changes to a ruby red color.

#4 Hydrangea arborescens- Smooth hydrangeas come in white and pink flowers. These need to be pruned hard in spring of the year before leafing out as well. Annabelle is probably the most popular, which is a white. They are smaller flowers and offer a dainty addition to the landscape. 

#5 Hydrangea petiolaris-Climbing hydrangea White to yellowish white flowers bloom in July. These climbers are great or an area where you need a vine but do not want it to be too invasive. They will cling to walls or trellises but need a little help to get started.

I have only touched on some of the different varieties of hydrangeas. Now is the time to purchase them as you can see what the blooms are all about. It seems every year 30-40 new varieties thanks to hybridization are coming out. Find ones that you like and water accordingly and feed them to have beautiful plants. They will reward you with an awesome display of flowers.