Getting it to bloom
Why won't my Silver Mullein bloom? (and how to make it flower)
Also called Silver Mullein, Giant Silver Mullein, Broussa Mullein (Verbascum bombyciferum).
More about silver mullein
About Silver Mullein
Verbascum bombyciferum · also called Silver Mullein, Giant Silver Mullein · flowering
Silver Mullein is a spectacular biennial from Turkey grown for its enormous silvery-white woolly rosettes and tall, branched spikes of sulphur-yellow flowers. The intense silver indumentum makes it one of the most ornamental of all mulleins, catching light dramatically in the garden. It thrives in full sun and sharply drained, poor to average soils, tolerating significant drought.
Plant type: flowering
The reasons silver mullein isn't blooming
Almost every non-blooming silver mullein traces back to one of these, roughly in order of how common they are:
- Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
- Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
- The plant has not been deadheaded, so it stops flowering once it sets seed.
- Irregular watering — drought or waterlogging at the budding stage makes buds abort.
- It is still too young or was checked by a transplant and is rebuilding before flowering.
Feeding silver mullein a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.
The fix — how to get silver mullein to flower
- Maximise sun. Give silver mullein the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
- Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
- Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
- Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.
Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for silver mullein and get the feeding right with the silver mullein fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.
Bloom season and what to expect
Silver Mullein flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.
Post-bloom care so it flowers again
Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.
For everything else this plant needs day to day, see the full silver mullein care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.
Silver Mullein blooming — frequently asked questions
Why won't my silver mullein flower?
Silver Mullein blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
How do I make silver mullein bloom?
Give silver mullein the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
When does silver mullein normally bloom?
Silver Mullein flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.
What should I do with silver mullein after it flowers?
Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.
What is the single biggest mistake stopping silver mullein flowering?
Feeding silver mullein a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.
Keep reading
- Silver Mullein care — the full brief (light, water, humidity, problems, pet safety)
- Silver Mullein light needs — usually the first thing to fix for flowers
- Silver Mullein fertilising — the right feed for buds, not just leaves
- Should I water my plant? The simple check
- Why is my plant wilting? Wet vs dry
- Underwatered plant — signs and rehydration
- Why won't my peace lily bloom?
- Why won't my jade plant bloom?
- Why won't my tomato bloom?
- All 3229 bloom guides in the Growli library