How to Grow Foxglove 'Excelsior Mix'
from Seed
The foxglove that flowers all the way around — the Excelsior strain holds its speckled bells horizontally around the stem rather than on one side, creating a dense cylinder of cream, pink, rose, and purple up to 1.5 metres tall; a woodland biennial beloved by bumblebees and the architectural backbone of the cottage garden
Among the biennials that define the cottage garden — foxgloves, honesty, sweet rocket, hollyhocks — the foxglove stands tallest, both literally and in the imagination. The wild British foxglove (Digitalis purpurea) produces its familiar downward-hanging bells on one side of the stem only; the Excelsior strain was developed specifically to produce flowers horizontally all around the stem, creating a much denser, more symmetrical cylinder of colour. The Bishy description captures this well: 'Unlike the wild forms that hang their bells on just one side of the stem, this improved heritage strain holds its flowers horizontally all around the stem, creating a dense, heavy cylinder of colour.'
The colour range of the Excelsior Mix — creamy white, soft pink, deep rose, and purple, all with the characteristic dark-speckled throats that give foxgloves their particular character — reflects the full natural variation in the species. Growing the mix from seed produces the same unpredictable tapestry of colour that appears in woodland edges where foxgloves naturalise, with individual plants producing their own distinct shade from within the range.
Quick Facts at a Glance
Plant Type
Hardy Biennial (H7) — extremely cold-hardy
Excelsior difference
Flowers horizontal all around stem — denser cylinder than wild type
Colours
Creamy white · soft pink · deep rose · purple — speckled throats
Height
Up to 1.5m — back-of-border architectural plant
Award
RHS Plants for Pollinators ✓
Difficulty
Understanding the Plant
Surface Sow — Foxglove Seeds are Dust-Like and Need Light to Germinate
Foxglove seeds are so fine they are barely visible individually — the Bishy page describes them as 'dust-like.' They must be sown on the surface of moist compost or soil with no covering or only the thinnest possible dusting of vermiculite. Any significant soil covering blocks the light stimulus required for germination. This is the single most common cause of foxglove germination failure.
⚠️ Toxicity Warning — All Parts Highly Toxic to Humans and Pets
All parts of the foxglove plant contain digitalis glycosides — the compounds from which the heart medication digoxin is derived — and are highly toxic if ingested by humans, dogs, cats, or other animals. The Bishy page specifically warns: 'We strongly recommend wearing gloves when handling the plants and keeping packets out of reach of small children.' Toxicity applies to all growth stages including leaves, flowers, and seeds.
Sowing & Growing On
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Sow indoors April–May or direct outdoors May–July; surface sow with NO covering. Scatter dust-like seeds on moist seed compost surface. Do not cover with soil — a very fine dusting of vermiculite is optional but not essential. Keep at 15–20°C. Germination in 14–21 days. Alternatively, scatter directly on a prepared outdoor seedbed in May–July; the seeds will germinate naturally in the moist conditions.
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Grow on in bright, cool conditions; avoid overwatering seedlings. Foxglove seedlings are susceptible to damping off in wet, stuffy conditions. Keep well-ventilated. Pot on into individual 7–9cm pots when large enough to handle. Grow on at 12–15°C — cool conditions produce the strongest, sturdiest plants.
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Move to final position September–October for winter establishment. The Bishy guide specifically recommends this: 'Move young plants to their final flowering positions in September or October so they can settle before winter.' A foxglove planted in autumn establishes a deep root system through winter and produces significantly taller, more robust spires in year two than one planted in spring.
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Plant in shade or partial shade in humus-rich, moist soil. Foxgloves are woodland-edge natives — they flower best in dappled shade, though they tolerate sun if soil remains moist. Adding leaf mould or well-rotted compost to the planting area produces the tallest, most impressive spires. Space 45–60cm apart.
Growing On & Care
The Woodland-Edge Ideal
Foxgloves are found naturally in the clearings and edges of deciduous woodland — the dappled light and moist, leaf-mould-rich soil of these positions matches exactly what the plant evolved for. In the garden, this means: under deciduous trees (where spring light reaches before the canopy closes), along north-facing fences, in the 'difficult shade' where sun-loving plants fail. In these positions, foxgloves provide essential vertical structure.
Long-Tongued Bumblebee Specialist
The RHS Plants for Pollinators designation for foxgloves relates specifically to long-tongued bumblebee species — primarily Garden Bumblebee (Bombus hortorum) — for which the deep, tubular bell is perfectly sized. The speckled 'nectar guides' inside the tube direct bees to the nectar. A tall foxglove spike in June is one of the most intensively worked plants in the garden.
Self-Seeding — Establishing a Permanent Colony
Foxgloves self-seed prolifically once established. Allow some of the seed capsules to ripen fully and split (late summer), scattering fine seeds around the parent plant. Self-seeded plants are often more vigorous than deliberately planted ones and establish the wandering colony that characterises a mature woodland garden. Edit seedlings in autumn rather than removing all of them.
Extending the Season — Lateral Side Shoots
After the main central spike has finished flowering, cut it down to the base of the plant rather than pulling it up. Secondary, smaller flower spikes often emerge from the base and from lateral shoots, extending the foxglove season by several weeks. These lateral spikes are shorter and less dramatic than the main spike but still valuable for pollinators and in arrangements.
Cut Flower Use
Foxglove spires are spectacular in large arrangements, providing vertical structure that no other cut flower quite matches. Cut when approximately a third of the bells from the bottom are open, with buds still showing at the tip. The remaining bells continue opening upward over the following days. Change water every two days. Wear gloves when handling cut stems.
Rust and Other Problems
Foxglove rust (orange powdery spots on leaves) can affect plants in poorly ventilated positions. Space adequately, water at the base only, and remove affected leaves promptly. Crown rot can occur in waterlogged soil — ensure good drainage. Slugs and snails target young seedlings — protect after transplanting with barrier or physical traps.
When to Sow and Flower
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Common Problems & Solutions
| Problem | Likely Cause | What to Do |
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| Few or no flowers | Biennial not yet at year two | Foxgloves sown in May–July flower the FOLLOWING year. If no flowers appear in the first summer/autumn after sowing, the plants are exactly on schedule. Move to final positions in September for winter establishment and expect flowers the following June. |
| Germination failure | Seeds buried; insufficient light | Foxglove seeds are tiny and photoblastic — they must be surface-sown with no covering. Re-sow on the surface of moist compost and do not cover. Germination in 14–21 days at 15–20°C. |
| Short or weak spires | Planted in spring; insufficient moisture | Autumn planting (September–October) produces the strongest plants. Rich, moist soil with added leaf mould or compost significantly increases spike height and density. A foxglove in poor, dry soil produces a thin, short spike; the same plant in moist, humus-rich soil produces a towering specimen. |
| Rust spots on leaves | Fungal; poor air circulation; wet leaves | Space 45–60cm apart for air circulation. Water at the base only, never overhead. Remove affected leaves promptly and dispose of (do not compost). Good air circulation is the primary preventive measure. |
Plant Specifications
The spire that defines the cottage garden — 1.5m cylinders of speckled bells flowering all the way around, for a June border with no rivals
Surface sow in May on moist compost. Move to a shaded, humus-rich position in September. Wait for June. The Excelsior foxglove's dense cylinder of cream, pink, rose, and purple speckled bells is the signature of the English cottage garden at its most complete — towering above lower-growing plants, providing the architectural vertical line that every garden needs, and feeding the long-tongued bumblebees that depend on it.
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