Why Is My Hydrangea Not Blooming? Causes and Fixes

More on hydrangeas

• Hydrangea planting zones — every type, the zones it suits, and when the last spring freeze lands in each zone
• Why Is My Hydrangea Not Blooming? Causes and Fixes — this page
• How to Prune Hydrangeas by Type: Old Wood vs New Wood
• How to Change Hydrangea Color: Blue or Pink by Soil pH
• How to Prune Limelight Hydrangea and Vanilla Strawberry
• How to Prune Annabelle and Incrediball Hydrangeas
• How to Prune Endless Summer Hydrangeas (Rebloomers)
• How to Prune Oakleaf Hydrangea: After It Flowers
• Hydrangea Pruning Chart: When to Prune Each Type
• Hydrangea Tree Care and Pruning (Tree-Form Panicle)
• Hydrangea Winter Care: Fall Pruning, Cages and Mulch
• ZIP code zone finder — your exact USDA zone, to read the tables on these pages against

Find your cause

Work down the list. The first “yes” is the likeliest cause.

1. Was it pruned between autumn and spring? On a bigleaf, mountain, oakleaf or climbing hydrangea, that removes the flower buds. Pruning at the wrong time
2. Did the stems die back over winter, or was there a freeze after growth started? Buds killed by winter cold or a late freeze
3. Was it a gift plant, or is your zone colder than its range? Same section, and check the zone table below.
4. Has it been fed with lawn fertilizer, manure or a high-nitrogen feed? Too much nitrogen
5. Is it under trees or on the north side of a building? Too much shade
6. Was it planted or moved in the last two or three years? Young or newly moved plants
7. Did it wilt in summer, or does it sit in clay that stays wet? Drought and heat stress
8. Do deer reach it? Penn State says heavy deer browsing on the old-wood types has the same result as a fall pruning: few or no flowers.

Which causes can apply to your type

Not sure which you have? Penn State says read the plant tag and ask at a nursery; Ohio State says that if the cultivar is unknown, watch the new growth for flower buds during the season.

Pruning at the wrong time

Penn State: most bigleaf varieties flower on old wood — wood that grew and set its flower buds the previous year — so if you cut back a hydrangea between the autumn and early spring, and it blooms on old wood, you have trimmed off all the future flowers. Penn State says the same of oakleaf hydrangea: pruned at the wrong time, it flowers less.

Ohio State says old-wood types set next year’s buds the year before, usually in August, and that cultivars pruned or cut down in fall will have little to no bloom the next year. Oregon State notes that the later and the harder you prune, the fewer flowers follow.

The fix: University of Minnesota Extension says prune bigleaf hydrangeas after they finish blooming and before August. Leave smooth and panicle hydrangeas, which flower on new wood, for late winter or spring. The pruning guide has every type.

Buds killed by winter cold or a late freeze

Penn State says bigleaf hydrangeas are winter hardy in zones 6 to 9 but can be killed to the ground in a cold winter, which means no flowers the following summer, and that even a moderately severe winter can kill or damage the flower buds. Early or late freezes can damage the buds too.

A gift hydrangea is a common case. Penn State says a hydrangea received for Easter or Mother’s Day, with foil or plastic around the pot, may be a florist’s hydrangea that is not winter hardy in Pennsylvania: the buds or stems freeze every year. The roots may be hardy, Penn State says, but the top of the plant is not.

Ohio State says that even the reblooming bigleaf types need protecting during April freezes, or the stressed plant will delay or reduce flowering. The freeze table on the hydrangea zones page shows when the last spring freeze lands in each zone, and how much later it comes one year in ten.

The fix, from Ohio State and Oregon State:

• Grow a type hardy in your zone, or one that flowers on both old and new wood (Ohio State).
• For old-wood types, Ohio State says protecting three buds is enough: prune back to just above the third bud and cover with mulch or a cage of leaves and compost. Take the protection off once new leaf buds begin to emerge.
• On nights a spring frost is forecast, Oregon State says cover the buds with bed sheets or frost cloth. Ohio State warns that winter protection is wasted if you forget the late frosts.

Too much nitrogen

Oregon State: Excess nitrogen encourages foliage at the expense of flowers. It recommends a slow-release, balanced fertilizer in spring, warns against animal manure because it tends to be too high in nitrogen (well-aged manure is acceptable), and says it is not always necessary to fertilize at all — most hydrangeas bloom better if a little starved.

Ohio State takes a slightly different line on bigleaf hydrangeas, which it says have heavy nutrient needs: a balanced fertilizer ensures growth and flowering through the season. Both point the same way — balanced, not high in nitrogen.

The fix: stop the high-nitrogen feed and switch to a balanced, slow-release one in spring (Oregon State). Penn State’s general advice for shrubs is to fertilize only as a soil test shows is needed: more fertilizer is not better.

Too much shade

Ohio State calls hydrangeas woodland plants, and says most species need some shade even when labeled for full sun. It says morning sun with afternoon shade is ideal for smooth, oakleaf, climbing and panicle types, that bigleaf needs more shade in the heat of the day, and that dense shade will result in reduced foliage and smaller flowers on some cultivars.

⚠️ That is the strongest statement on shade in the sources we read. None of them says shade alone stops a hydrangea flowering, so treat shade as a cause to check after pruning, cold and feeding.

The fix: Oregon State says many hydrangeas prefer morning sun and afternoon shade, and that planting is best avoided in hot weather; spring through early fall is ideal. If a plant has to move, see the next section first.

Young or newly moved plants

The sources we read give no general number of years before a young hydrangea flowers. Two say something close:

• Ohio State says climbing hydrangea grows slowly for its first three years, grows rapidly once established, and that its flowers become numerous once established.
• Penn State, writing about moving established shrubs in general rather than hydrangeas, says a moved shrub may sulk for two or even three growing seasons.

The fix: patience, and water. Penn State says a moved shrub needs deep, regular watering for at least one full growing season, and no fertilizer at planting. Oregon State says large hydrangeas are best moved in spring or fall, and that on young plants you should prune only enough to form a good shape.

Drought and heat stress

Ohio State lists plant stress from poor soil — mostly clay, slow to drain — as another reason for missing flowers, and says to water bigleaf hydrangeas during dry spells and whenever they are exposed to hot sun. Bigleaf has the highest water needs of the hydrangeas and oakleaf the lowest, it says.

Oregon State’s heat-wave bulletin says bigleaf hydrangeas are less tolerant of drought and heat, that a heat wave left their flowers with brittle tan edges, and that a severely damaged plant may not regain its former glory until the next summer. Panicle is the most adaptable type and tolerates drier conditions, it says, but none of them should be considered drought-tolerant.

Signs: Oregon State says droopy leaves that perk up within half an hour of watering mean too little water; brown leaf edges and leaf drop can mean too much.

The fix, from Oregon State:

• Water deeply with a soaker hose or slow drip; a quick hand watering only wets the surface.
• Mulch with bark to hold moisture; avoid gravel and black plastic, which raise soil temperatures.
• After heat damage, do not prune hard, which pushes tender new growth, and do not fertilize.

Common mistakes

• Cutting an old-wood hydrangea back in fall or spring. That removes the flower buds (Penn State).
• Covering against winter and forgetting the late frosts. Ohio State says the effort is then wasted.
• Feeding with lawn fertilizer or fresh manure. Too much nitrogen gives leaves, not flowers (Oregon State).
• Moving a struggling plant in summer heat. Oregon State says move large ones in spring or fall.
• Giving up after one year. A moved shrub may sulk for two or three seasons (Penn State).
• Watering lightly and often. Oregon State says water deeply; a quick sprinkle wets only the surface.

In the South

In Florida, UF/IFAS says French (bigleaf) hydrangeas do best in North and Central Florida and need shade, moist fertile soils and cool winters. We found no Texas source on hydrangeas, so Texas advice here is limited; ask your county AgriLife Extension office.