Bloomstruck hydrangea is a cultivar of Hydrangea macrophylla known for its large, vibrant flowers, which range in color from pink to purple and even blue, depending on the acidity of the soil. These compact flowering shrubs are a re-blooming type of hydrangea, growing flowers both on old overwintered wood and new spring growth. These low-maintenance plants are absolutely stunning in the garden and home landscape.
Bloomstruck hydrangea basics
The Bloomstruck Hydrangea (Hydrangea macrophylla ‘PIIHM-II’) is a deciduous flowering shrub with gorgeous mophead-type hydrangea flowers. These plants typically bloom from July to August but can bloom slightly earlier in the spring if the conditions are correct. The BloomStruck® Hydrangea is sold by Endless Summer®, which is also known for its original Endless Summer hydrangea variety and the newer Summer Crush variety.
The reddish-purple branches are largely covered by dark green leaves, especially during the summer months. Branches set overwintering flower buds in the fall, which then bloom early the next spring. This plant is a reblooming type of hydrangea and also grows flower buds on fresh green spring stems.
Bloomstruck hydrangea grows to be 3 to 4 feet tall and can grow to be 4 to 5 feet wide. These are plants that take up a large amount of space, so make sure that when you plant your hydrangeas, you do not plant them too close to each other.
The Bloomstruck Hydrangeas grow flowers in large bunches. This type of hydrangea is well known because the flowers can change color based on the pH level of the soil. Garden lime can be used to turn Bloomstruck hydrangea flowers into a vibrant pink color. Soil acidifier can be used to turn Bloomstruck hydrangea flowers purple or blue (see details in the following sections).
Bloomstruck hydrangea plants
BloomStruck® Hydrangea is an Endless Summer® bigleaf hydrangea cultivar. Endless Summer is a very popular brand, and it is carried by most garden centers. If your local plant nursery doesn’t stock it, they may be able to order it for you. You can also order shrubs online now.
How to plant Bloomstruck hydrangeas
It is very easy to plant Bloomstruck hydrangeas. They grow best when in partial shade, but they will grow in full sun where the sun is not overly harsh and the plant is well-watered. In very warm climates, it is best to plant Bloomstruck Hydrangeas in partial shade rather than in full sun because the flowers can become dry or scorched if they are in direct mid-day or afternoon sunlight for too long.
When you plant a Bloomstruck hydrangea, dig a hole that is about twice as wide as the planter but no deeper than the soil inside the pot. Remove the plant’s pot and place your hydrangea into the hole. Make sure that you plant your Bloomstruck Hydrangea in soil that drains well and is fertile so your plant has enough nutrients to grow.
After you cover the root ball in the soil, water the area around the Bloomstruck Hydrangea until the soil is moist but not wet. If you do not want to water your hydrangea frequently or do not want to check the soil often, add mulch to the top of the soil. The mulch will help preserve the moisture in the soil so you can water your Bloomstruck Hydrangea less frequently.
You should see your Bloomstruck Hydrangea bloom during the summer after planting it, but don’t worry if it does not bloom that year (or has only a couple of flowers). It may need some time to get used to its new environment, or you may have planted it too late in the season for it to properly bloom on time. This perennial plant will be back next year, so you can look forward to it blooming then.
Changing the color of Bloomstruck hydrangea flowers
Bloomstruck is a cultivar of Hydrangea macrophylla, which is the type of hydrangea that can change its blossom color based on the pH of the soil. A garden soil test will tell you the baseline soil pH so you can decide how to amend the soil (and change the flower color).
Garden lime can be used to turn Bloomstruck hydrangea flowers into a vibrant pink color. Alkaline soil amendments like dolomite lime raise the pH of acidic soils to bring them to a more neutral level. Garden lime is typically applied in early spring and/or early fall until the desired neutral pH (7.0 for pink) is reached.
Soil acidifier can be used to turn Bloomstruck hydrangea flowers purple or blue. Acidifiers like sulfur and gypsum lower the pH of soils to produce purple/blue blooms. Soil Acidifiers are typically applied every few months until the desired soil pH (5.5-6.5 for purple, 4.5-5.0 for blue) is reached.
Fertilizing Bloomstruck hydrangea plants
Bloomstruck hydrangea plants can benefit from an annual application of well-balanced, slow-release organic fertilizer. Bloomstruck plants are typically fertilized in early spring as they come out of winter dormancy.
Pruning Bloomstruck hydrangea
You do not have to prune Bloomstruck Hydrangeas, but doing so can promote new blooms, especially if the winter season is harsh on the plant and overwintered buds have died. If you do want to prune your Bloomstruck Hydrangea after a harsh winter, do so in the late winter or early spring, before the growing season begins.
Routine pruning of Bloomstruck Hydrangea is best done right after the blooms have finished in the summertime. This allows the plant to set new buds in the fall, which will overwinter for an early spring show of flowers. If you want to keep the Bloomstruck Hydrangea flowers, cut the branch that supports the flowers where the two branches meet. This will not damage the rest of the hydrangea, and may even promote new growth.
Common pests affecting Bloomstruck hydrangea
Bloomstruck Hydrangeas can be attractive to pests, including aphids, spider mites, slugs, and Japanese beetles. Fortunately, recognizing them is fairly straightforward. These pests are all possible to conquer if you have the right tools.
First, wash as many bugs/pests as possible off the plant with a sharp stream of water. Then try to increase air circulation by pruning both the shrub itself and its nearby neighbours. Lastly, treat with a natural pesticide if the problem persists.
Diseases affecting Bloomstruck hydrangea
While Bloomstruck hydrangeas are more resistant to disease than some similar varieties, they are still susceptible to several plant diseases, including powdery mildew, bud blight, leaf spot, and bacterial wilt. Most of these are caused or exacerbated by overwatering, too much shade, or too little ventilation within your plant.
To treat disease, start by increasing air circulation by pruning. A more drastic solution is to transplant it to an area (such as somewhere with better-draining soil). You can also try organic fungicides.