Hydrangea not blooming? Here's what to do

Hydrangea not blooming?  Here's what to do

Oakleaf hydrangea grows but does not bloom

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Gatsby pink oak leaf hydrangea

“I have a 7-year-old oak leaf hydrangea in a shady spot. It grows so much healthy foliage that I have to prune it regularly, but my hydrangea doesn't bloom. It only blooms once or twice. Why do you think that is?” asks William Stovall.

It's all about timing when pruning this and other hydrangeas. Oakleaf hydrangea plants produce flower buds the year before they open. Keep pruning to a minimum to maximize flower display. Remove only damaged and stray branches every year as needed. This helps control the size of the plant while encouraging it to flower. Heavy pruning stimulates growth and results in a larger plant that needs additional pruning. Selective pruning leaves you with more stems with healthy flower buds for better blooms the following year.

Trim like a pro: Study the shape of the plant before making any cuts and be sure to always use clean, sharp tools. Avoid over-pruning by cutting only a quarter to a third of the canopy annually.

Check out hydrangea facts that even expert gardeners don't know.

Large-leaved hydrangea does not bloom

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Nikko Blue Bigleaf Hydrangea

“My large-leaf hydrangeas have not bloomed in the last two years (and had limited blue flowers before that).” I don't stop until I see green shoots in the spring. What's the problem?” reader Don Lieber asks.

Large-leaved hydrangea (Hydrangea macrophylla) Flower buds form on stems from the previous flowering season. In cold climates like yours, the plants often die back to the ground, eliminating the flower buds so that all you're left with is a leafy shrub. Repeated large-leaf hydrangea varieties are supposed to have two sets of flowers, with the first bud set the previous year and the second on new growth.

Leave the hydrangea to stand over the winter and cover the soil around it to increase the chance that the flower buds will survive the cold. Only remove dead stems in spring, which may mean pruning to ground level.

Fertilize the plants in the spring and keep the soil moist but not wet to encourage flowering. I have seen success using Milorganite nitrogen fertilizer that contains non-leaching phosphorus. Research has found that when microorganisms release nutrients from milorganite granules, some soil-bound phosphorus and potassium also become available to plants. Phosphorus promotes flowering, fruiting and root development, while potassium helps with hardiness and disease resistance.

Make sure you know these basic tips about hydrangea care.

Climbing hydrangea does not bloom

Hydrangea does not bloomCatherine McQueen/Getty Images
A trellis covered with climbing hydrangeas

“My 6-year-old climbing hydrangea has not flowered. It is 15 feet tall and spreading up a trellis. How can I encourage flowering? Asks Alyssa Caddick.

You are definitely not alone. Hydrangea not blooming is a common problem among gardeners who grow climbing hydrangea. As you have discovered, these plants take a long time to become established and begin flowering. Avoid high-nitrogen, rapid-release fertilizers that encourage leaf and stem growth but discourage flowering.

Water plants well as needed and use a low-nitrogen, slow-release fertilizer if you feel your plants need a boost. Beautiful flowers will grow as a reward for your patience.

Are you looking for a new hydrangea color to add to your garden? Try 'Wee Bit Giddy' hydrangea.

Protect hydrangeas in the winter

Large-leaved hydrangeaVia confirmed winners
City Line Berlin Cuban

“My hydrangeas are about 15 years old and have only flowered once. I feed them and cover them with pine needles and leaves in the winter. What am I doing wrong?” Loretta McClincy asks.

Most large-leaved hydrangeas (Hydrangea macrophylla), with pink or blue flowers, produces flowers only on the previous season's growth. Also known as mophead hydrangea. The flowers bloom pink in alkaline soil and blue in acidic soil. (Learn how to change the color of hydrangea.)

If it dies back to the ground or is pruned to the ground in late winter, it will not flower. In your climate, you need to protect future flowering from the cold.

Try surrounding the plant with a 4-foot tarp. Plant it several inches into the ground to keep out rabbits and voles, then fill it with weed-free straw or evergreen branches to insulate the plant. Wrapping your fence with burlap or a weed barrier will add another layer of insulation.

Pink and blue hydrangea hedge.AZDC/Getty Images

You may also consider placing evergreen branches or weed-free straw over the plants after the ground freezes. This mulch provides better insulation than leaves. In the spring, remove the mulch and wait to see if there is any growth on the stems. This is growth that will flourish. You should prune only the dead parts of the stems.

If you are planting one of the large-leaf hydrangeas that blooms repeatedly, such as the Endless Summer variety, make sure the soil is moist and fertilized with a low-nitrogen organic fertilizer once in the spring. These varieties are meant to thrive on both old and new growth with proper care.

Many Northern gardeners have switched to hardier hydrangeas, whose flowers start out white and then fade to pink. Moisture and proper fertilization are the key to success.

Discover more breathtaking types of hydrangea.

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