Why won't my mature lavender plant bloom?

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Published: September 17, 2025

Updated: September 17, 2025

Gardens are often perplexed by fully mature lavender shrubs with lush green foliage that fail to flower. This frustrating phenomenon is likely due to four basic care errors. Knowing these potential mistakes will help you avoid them. I often made the same blunders I share below while I had my lavender hedge, until I changed how I cared for it. The proper correction will reward you with a lot of flowers.

Nutritional Imbalances

Excess nitrogen promotes leafy growth over flowers
Solution: Apply low-nitrogen fertilizer (5-10-10) in early spring
Avoid: High-nitrogen formulas after bud formation begins
Test soil annually to maintain balanced nutrient levels

Environmental Factors

Insufficient sunlight below 6 hours daily prevents blooming
Solution: Transplant to south-facing locations or prune shading plants
Overwatering during bud stage causes flower abortion
Solution: Water only when top 3 inches of soil dry completely

Bloom Failure Diagnosis Guide
Symptom	Likely Cause	Corrective Action
Lush leaves, no flowers	Excess nitrogen	Apply phosphorus-rich fertilizer
Sparse, leggy growth	Insufficient light	Relocate or supplement with grow lights
Woody base, few stems	Improper pruning	Prune only green growth annually

Based on Royal Horticultural Society lavender trials

Bloom Failure Diagnosis Guide

SymptomLush leaves, no flowersLikely CauseExcess nitrogenCorrective Action

Apply phosphorus-rich fertilizer

SymptomSparse, leggy growthLikely CauseInsufficient lightCorrective Action

Relocate or supplement with grow lights

SymptomWoody base, few stemsLikely CauseImproper pruningCorrective Action

Prune only green growth annually

Based on Royal Horticultural Society lavender trials

The technique of pruning will affect flowering potential. Cutting into woody stems kills the regeneration points. Prune only above green growth and after it has flowered. I make mounds of my plants each July. This gives them new flowering wood for next season.

The length of time that plants receive sunlight is a hard and fast rule for flowers. Lavender requires full sun to form buds: six hours or less results in no flowers. My plants were in the shade of trees, and never flowered until they were moved, tracking where the sun is during the growing season.

Controlling soil moisture during bud formation is vital. Too much irrigation removes important nutrients. Water thoroughly once the soil is bone dry. I use a probe to measure moisture before I water. This helps avoid soft swelling buds from dropping early.

Growing lavender requires patience. Plants that were previously stressed may take a season to recover. My lavender, which I had neglected for two years, bloomed profusely this year. If you care for your lavender consistently, it blooms stronger than before.

Read the full article: How to Grow Lavender From Seed Successfully

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