Florence fennel boltsA plant switching early into flowering and seed production, usually triggered by stress, after which leaves, roots or bulbs turn bitter or unusable. Full page → easily, so the bulb either doesn't form or turns woody. It does best in warm, damp summers and may be less successful in colder regions, which makes the variety worth choosing with care in Scotland.
Quick answer
Dragon, which is resistant to bolting. Rondo for a quick-growing, early crop, and Zefa Fino for a quick-maturing bulb, though it makes no claim to resist bolting.
What Scotland means for the choice
Three things set Florence fennel bolting: cold in spring, root disturbance when it's transplanted, and dry spells in summer. Most varieties are bolt-resistant, which helps where conditions aren't ideal, but none is immune: early sowings are the most likely to bolt, so for most varieties sow in early to mid-summer once it has warmed up. Perfection is the exception recommended for an earlier sowing. It does best in warm, damp summers and may be less successful in colder regions and in heavy clay, so in a cooler garden a bolt-resistant variety is the safer choice. The bulb takes three or four months to mature, but you can harvest at any size, even as mini veg after about six weeks, which suits a short season. The Florence fennel growing guide covers sowing, transplanting and watering, and the bolting page explains the triggers.
| Variety | Known for |
|---|---|
| Dragon | Resists bolting and yellowing; compact, about 75cm tall, H5The RHS's H1a–H7 scale for how much cold a plant can survive outdoors, H1a being tender indoor-only and H7 hardy anywhere in the UK. Full definition → |
| Rondo | Quick-growing early cropper with uniform bulbs, H5 |
| Zefa Fino | Quick-maturing, medium to large, slightly flattened bulbs |
| Perfection | Bolt-resistant; medium bulbs, delicate aniseed flavour; good for early sowing |
| Cantino | Bolt-resistant; strong flavour |
| Amigo | Bolt-resistant; regular, slightly flatter bulbs |
| Colossal | Bolt-resistant; very large bulbs |
Dragon and Rondo hold the RHS Award of Garden Merit (AGMThe RHS's Award of Garden Merit: a UK-wide trials award for reliable performance, not a Scotland-specific recommendation. Full definition →). Zefa Fino doesn't. Perfection, Cantino, Amigo and Colossal are recommended by Gardener's World.
Dragon, Rondo and Zefa Fino
Dragon is a compact F1 hybridThe first-generation offspring of two specific, deliberately chosen parent plants, bred for a predictable, uniform result but not worth saving seed from. Full definition → about 75cm tall, with feathery foliage and rounded, swollen, aniseed-flavoured stems. It's resistant to bolting, though it can still flower if it's stressed by dry, hot weather or the bulb isn't harvested. Rondo is quick-growing and an early cropper, with uniform bulbs. Zefa Fino is quick to mature, with slightly flattened, medium to large bulbs, but it has no stated bolting resistance, so give it steady water.
Perfection, Cantino, Amigo and Colossal
All four are bolt-resistant. Perfection makes medium bulbs with a delicate aniseed flavour and suits early sowing, Cantino has a good, strong flavour, Amigo gives regular, slightly flatter bulbs, and Colossal makes a very large bulb.
Buying seed
Florence fennel is closely related to herb fennel, and both are often sold simply as "fennel", so check the packet says Florence or bulb fennel. Bronze fennel is a herb fennel, grown for its leaves, and won't make a bulb. Seed is easy to find in garden centres and online. Some suppliers sell plug plants in spring and early summer, but transplanting is one of the things that sets fennel bolting, so seed is the safer start. The bulb has a sweet, mild aniseed flavour that goes well with fish.
Which one for your situation
- The safest choice for a cool or unpredictable summer: Dragon.
- An early crop: Rondo.
- A quick-maturing bulb, with steady watering: Zefa Fino.
- The biggest bulb: Colossal.
- A stronger flavour: Cantino.
Common questions
Which Florence fennel is least likely to bolt?
Dragon, which is resistant to bolting. Most varieties are bolt-resistant, but Zefa Fino has no stated resistance.
Is bronze fennel the same as Florence fennel?
No. Bronze fennel is a herb fennel, grown for its leaves and seeds, not a bulb. Herb fennel and Florence fennel are often both sold simply as fennel, so check the packet says Florence or bulb fennel.
When should I sow Florence fennel?
In early to mid-summer, once temperatures have warmed up. Early sowings are very liable to bolt.
Can I harvest Florence fennel small?
Yes. You can harvest at any size, even as mini veg after about six weeks, and a full bulb takes three or four months.
Sources
Show the 5 sources
- Florence fennel: grow your own: The three recommended varieties and AGM status; bolting and its three triggers; warm, damp summers, colder regions and heavy clay; most varieties bolt-resistant; sowing in early to mid-summer; buying seed and plug plants; flavour; mini veg and harvest times
- Fennel (herb): grow your own: Herb and Florence fennel both sold as fennel; bronze fennel is a herb fennel
- Foeniculum vulgare 'Dragon': H5; about 75cm; resistant to bolting; can flower in dry, hot weather
- Foeniculum vulgare 'Rondo': H5; Florence fennel grown for its swollen leaf bases
- How to grow fennel: Perfection, Cantino, Amigo and Colossal; bolting after a shock