Are hydrangeas not blooming? 7 Reasons Why and How to Fix the Problem

7 Reasons Why and How to Fix the Problem

What happens when your hydrangeas don't bloom by the time you see other hydrangeas in bloom? If your plants look generally healthy, the good news is that the problem can usually be fixed and you can enjoy the blooms from your hydrangeas again. Here are 7 common reasons why hydrangeas don't bloom. Once you figure out what's causing your plant to stop blooming, use the tips in this guide to fill your garden with plenty of hydrangea blooms again. 

1. Pruning at the wrong time

Pruning at the wrong time of year is the most common reason hydrangeas fail to bloom. Pruning at the right time starts with deciding what type of hydrangea you are growing. Here's a trick: If your hydrangea doesn't bloom in spring, it only blooms in mid-to-late summer, a tender hydrangea (Hydrangea arborescens) or panicle hydrangea (Hydrangea paniculata) and produces flower buds in spring. Since both tender and panicle hydrangeas form flower buds and bloom in the same growing season, they can be pruned in early spring.

Spring and early summer blooming hydrangeas are bigleaf hydrangeas (Hydrangea macrophylla) or oakleaf hydrangeas (Hydrangea curcifolia). These hydrangeas bloom from flower buds that formed the previous summer or fall. The best time to prune bigleaf and oakleaf hydrangeas is early summer, right after they bloom.

What to do: Prune your hydrangea on time and avoid cutting flower buds. If you make a pruning mistake, let the plant bounce back and flower before pruning the next season.

2. Winter injury

Oakleaf and bigleaf hydrangeas form flower buds in late summer and fall the following spring. Delicate flower buds must survive winter to bloom in spring. Blasts of severe cold and frost damage can destroy flower buds. In zone 5 and below, susceptible hydrangeas will bloom when they have winter protection. Hydrangeas in Zone 6 may also benefit from winter protection.

Dry conditions in the fall also contribute to winter damage and lack of blooms. Any variety of hydrangea that goes into winter with dry stems and roots is more likely to experience winter injury.

What to do: First, water the plants deeply in the fall. Protect the tender flower buds of susceptible hydrangeas from severe cold. This can be done by creating an insulating cylinder around the bush in late November, using sturdy stakes and chicken wire or burlap. Fill the cylinder with leaves or straw. Remove the cylinder and leaves in early spring.

3. Deer damage

The tender stalks and succulent buds make a welcome snack for deer. Hydrangeas are commonly browsed by deer year-round. Winter browsing removes flower buds on oakleaf and bigleaf hydrangeas while growing season browsing removes flower buds on panicle and tender hydrangeas.

What to do: Protect plants with a barrier or deer-repellent spray. Barriers such as fencing or web-style wrap are useful but unsightly in most cases. Deer repellent is invisible and often effective. Sprays should be diligently reapplied after each shower. If the deer is insensitive to a particular spray, try a different brand.

4. Too much nitrogen

Nitrogen fertilizers promote deep green leaves, but few flowers. Avoid fertilizing your hydrangea with a high-nitrogen fertilizer. If you don't fertilize your hydrangea, it may still suffer from excess nitrogen due to nearby soil. Lawn compost is often high in nitrogen and can wash into the soil around the hydrangea.

What to do: When fertilizing hydrangeas, choose a material that is higher in phosphorus than nitrogen to encourage flower production.

5. Late Freeze

A late spring freeze can destroy developing flower buds. Hydrangeas are particularly susceptible to moderate early growing days and late frosts even when the hydrangea is actively growing.

What to do: Pay attention to the weather forecast in spring. If a late freeze is predicted, protect your plants from frost with sheets or blankets. Place the envelope on the floor Use bricks, rocks, or anything heavy for protection.

6. Not enough light

Hydrangeas grow best when they receive bright morning light and partial shade in the afternoon. Plants that thrive in more shade have few flowers and long, flexible stems.

What to do: Move hydrangea planted in too much shade to a brighter growing area. The best time to transplant hydrangea is early spring.

7. Hydrangea species

Some varieties of hydrangeas have a reputation for being finicky when in bloom, even if there is no sign of winter damage, deer will not defoliate the plant, timely pruning, and excess nitrogen is not a problem. One year they unfurl abandoned flowers, and the next year only a flower or two adorn their leafy stems.

Bigleaf hydrangeas often fall into this category of unpredictable blooming patterns. Additionally, if you have potted florist hydrangea, these plants are forced to bloom out of season (for example, Mother's Day hydrangeas) and are intended to bloom once indoors. These hydrangeas are unlikely to rebloom even if you plant them outside.

What to do: Choose a variety of hydrangeas that blooms regularly, such as panicle, smooth, and oakleaf varieties.