Crocosmia ‘George Davison’ (Montbretia): Complete Growing Guide

Why Grow ‘George Davison’

Among the many Crocosmia cultivars available, ‘George Davison’ stands out for its unusually warm, golden-yellow flowers — a departure from the more common reds and oranges that dominate the genus. The colour is closer to amber or deep buttercup than the harsh egg-yolk yellows found in some plants, and it softens beautifully against the backdrop of its own sword-shaped, mid-green foliage. It’s this combination of warm colour, elegant arching flower sprays, and easy-care nature that earned ‘George Davison’ the Royal Horticultural Society’s Award of Garden Merit (AGM).

A hybrid of Crocosmia aurea and Crocosmia pottsii, this montbretia grows from underground corms that multiply steadily to form expanding clumps. From midsummer to early autumn, arching stems carry sprays of tubular flowers that open from orange-tinted buds — the contrast between the warm orange buds and the golden-yellow open flowers adds visual depth that you don’t get with single-colour plants.

Growing 2–3 feet (60–90 cm) tall, ‘George Davison’ is compact enough for the middle of the border yet substantial enough to create real impact when planted in drifts. It’s hardy to USDA zone 5 (zone 6 with protection in the UK), drought-tolerant once established, and attractive to hummingbirds and butterflies. The flowers are also exceptional as cut stems — they last well in water and add a late-summer warmth to arrangements that’s hard to replicate with other cut flowers.

Quick Reference

Care Guide

Light

Full sun produces the best flowering and the sturdiest stems. Six or more hours of direct sunlight daily is ideal. ‘George Davison’ tolerates light shade — perhaps dappled afternoon shade from a deciduous tree — but expect reduced flower production and slightly taller, leaner growth.

In very hot climates (zones 8–9), some afternoon shade actually helps the flowers last longer and prevents scorching. But for most gardens in zones 5–7, plant in the sunniest spot available. A south- or west-facing border that catches the afternoon sun is the sweet spot: warm enough to encourage good flowering, with the soil warming up quickly in spring to bring the corms into growth early.

Soil

Crocosmia prefers fertile, moist but well-drained soil — the kind that stays evenly damp during the growing season but never sits waterlogged. It’s more tolerant of clay than many bulbous plants, which makes it a useful choice for heavier soils where alliums and tulips would struggle, provided the clay doesn’t become waterlogged in winter.

Before planting, work in plenty of organic matter (garden compost, well-rotted manure, or leaf mould) to improve both moisture retention and drainage. In very sandy soils, the organic matter is especially important to prevent the corms drying out during active growth. A slightly acidic to neutral pH (6.0–7.0) is ideal, but Crocosmia adapts to a wide range.

Planting Corms

Plant corms in spring once the risk of hard frost has passed — typically March to April in most zones. This gives them the entire growing season to establish before their first winter.

Depth: Plant corms at roughly three times their own depth — typically 3–4 inches (8–10 cm) deep from the top of the corm to the soil surface. Planting too shallow exposes corms to frost; too deep delays emergence.

Spacing: Set corms 4–8 inches (10–20 cm) apart, with the slightly pointed end facing upward and any visible roots downward. Closer spacing (4–6 inches) creates a denser, more immediate display; wider spacing (8 inches) gives the clump room to naturalise over several years.

Orientation matters: Crocosmia corms have a definite top and bottom. The pointed tip goes up; the slightly flattened base (where last season’s roots were) goes down. If you can’t tell, plant them on their side — the shoot will find its way up.

Water thoroughly after planting. In zones 5–6, cover the planting area with a 2-inch (5 cm) mulch layer to insulate corms against late spring frosts.

Watering

During the active growing season (spring through flowering), keep the soil evenly moist — especially during bud formation, when water stress can reduce flower quality and quantity. Water deeply once or twice a week in dry spells rather than little and often.

Once established (after 2–3 growing seasons), ‘George Davison’ develops good drought tolerance thanks to its corm-based water storage. Established clumps in the ground typically survive dry periods without supplemental watering, though flowering will be reduced during prolonged drought.

After flowering, as the foliage yellows and dies back, reduce watering. The corms are dormant in winter and need relatively dry conditions.

Feeding

Ground-planted Crocosmia in reasonably fertile soil rarely needs supplemental feeding — the organic matter worked in at planting time provides sufficient nutrition. The RHS notes that ground-grown plants don’t need feeding at all [1]. If soil is poor, a light application of balanced slow-release fertiliser in early spring as shoots emerge is adequate.

Container-grown plants are a different matter: they benefit from fortnightly feeds with a high-potassium liquid fertiliser (tomato feed works perfectly) throughout the summer months [1].

Post-Bloom Care

After flowering, leave the foliage intact until it yellows and dies back naturally — the leaves are still photosynthesising and feeding next year’s corms. Don’t cut or braid the foliage; just let it go. Once fully yellowed (usually by late autumn), remove the dead leaves to tidy up.

The spent flower stems can be cut back to the base once all the flowers have faded, or left for a few weeks for their architectural silhouette. The seed heads aren’t particularly ornamental, so most gardeners remove them promptly to direct energy back into the corms.

Winter Care

In zones 7–9, Crocosmia ‘George Davison’ overwinters happily in the ground with no special protection. In zones 5–6, apply a thick layer (3–4 inches / 8–10 cm) of organic mulch — straw, bark chips, or garden compost — over the planting area in late autumn to insulate the corms from hard freezes. Remove the mulch gradually in early spring as temperatures rise.

In the coldest areas (zone 5 or exposed gardens in zone 6), consider lifting corms in late autumn: dig them up after the foliage has died back, dry them for a few days in a cool, airy spot, and store in trays of barely damp sand in a frost-free shed or garage. Replant in spring. I’ve found that ‘George Davison’ is hardier than many Crocosmia cultivars — mine have survived zone 6 winters without lifting for several years — but lifting is insurance if your winters are unpredictable.

Propagation

Division (Recommended)

Division is the best method — it’s easy, reliable, and maintains the cultivar’s characteristics exactly. Divide every 3–5 years in early spring, just as new growth appears.

Dig up the entire clump, and you’ll see a chain of corms stacked on top of each other (each year’s new corm forms on top of the previous year’s). Carefully separate individual corms or small groups, each with at least one growing point (an “eye” or emerging shoot). Replant immediately at the same depth and spacing, water well, and they’ll establish quickly. Most divisions flower in their second year after splitting.

Division also solves the most common Crocosmia problem: overcrowding. Left undivided for too long, clumps become congested, flowering declines, and the centre of the clump becomes unproductive. Regular division keeps the display fresh and vigorous.

Seed

Seed propagation is possible but slow. Collect seed from mature seed heads in autumn, sow in trays of seed compost, and keep in a cold frame over winter. Germination occurs in spring. Seedlings take 2–3 years to reach flowering size and may differ from the parent plant. For most gardeners, division is far quicker and more predictable.

Cormlets

Each year, a Crocosmia corm produces one or more daughter corms (cormlets) on top of or beside the mother corm. This natural multiplication is what creates the expanding clumps over time. When dividing, you’ll notice these chains of corms stacked like coins — the youngest (and most vigorous) are at the top, the oldest (and most depleted) at the bottom. When separating, prioritise the top corms with visible growing points, as these establish fastest and flower soonest. Old, shrivelled corms at the base of the chain can be discarded.

Saving Corms for Replanting

If you need to store corms over winter (in very cold zones or when reorganising the garden), dig them up after the foliage has fully died back. Shake off excess soil, allow to air-dry for 2–3 days in a cool, airy location out of direct sun, then store in paper bags or trays of barely damp sand. Keep in a frost-free spot (shed, unheated greenhouse, or cool garage) at around 5–10°C (40–50°F). Check periodically for rot and discard any soft or mouldy corms. Replant in spring.

Common Problems and Solutions

Overcrowding and Declining Flowers

The most frequent complaint. Crocosmia clumps multiply steadily, and after 3–5 years the corms become so congested that flowering drops off sharply. The solution is straightforward: dig up, divide, and replant with proper spacing. Do this in early spring for best results.

No Flowers in First Year

Completely normal. Newly planted corms put their energy into root establishment and may not flower until their second season. If an established clump stops flowering, it’s usually overcrowding (divide) or insufficient sun (move or prune overhanging vegetation).

Corm Rot

Caused by waterlogged soil, particularly in winter. The corms soften and decay rather than sprouting in spring. Prevention: ensure good drainage before planting, avoid low-lying areas that collect standing water, and don’t overwater during dormancy. Infected corms should be dug up and discarded — don’t compost them.

Red Spider Mite

Occasionally problematic in hot, dry conditions — tiny mites cause stippled, yellowing foliage. Increase humidity by misting (in greenhouse culture) or water regularly during dry spells. Severe infestations can be treated with insecticidal soap.

Thrips

Thrips can cause silvering and distortion of leaves and flowers. Insecticidal soap or neem oil applied at the first sign of damage is the most effective treatment.

Invasiveness Concerns

An important note: Crocosmia × crocosmiiflora (the species group that includes ‘George Davison’) is classified as invasive in the UK and several other regions. The RHS warns that it’s illegal to plant it, or cause it to grow, in the wild in the UK [1]. In garden settings this is manageable — the clumps expand but don’t aggressively run. However, never dump unwanted corms into green waste bins, compost heaps, or wild areas. Dispose of removed corms responsibly: bag them and put them in household waste, or dry them thoroughly and burn them.

Garden Design and Companion Plants

Design Uses

The arching flower sprays of Crocosmia create a graceful, semi-naturalistic effect that works in both formal borders and wilder settings. ‘George Davison’s’ golden-yellow flowers are particularly versatile — they complement both warm and cool colour palettes without clashing.

Plant in drifts of 7–15 corms for the best effect. The sword-shaped foliage provides structural interest even before the flowers appear, and it integrates beautifully with ornamental grasses and other late-summer perennials. In cottage gardens, ‘George Davison’ adds a relaxed, old-fashioned charm; in prairie-style plantings, it echoes the warm tones of the landscape.

The cut flower value is exceptional — stems last 10–14 days in a vase, and the arching form adds movement and elegance to arrangements that upright flowers can’t match.

Companion Plants

• Rudbeckia hirta ‘Prairie Sun’ — golden daisies echo the yellow tones and bloom simultaneously. The upright daisies and arching Crocosmia sprays create a dynamic textural combination.
• Echinacea ‘Sundown’ — sunset-orange coneflowers add a warmer tone. Both are midsummer bloomers with similar moisture needs.
• Miscanthus sinensis ‘Gracillimus’ — fine-textured grass provides a foil for the bolder Crocosmia foliage and adds autumn interest after flowering.
• Salvia ‘Hot Lips’ — red-and-white bicolour flowers create a lively contrast against the golden-yellow Crocosmia.
• Dahlias — late-summer companions with bold flower forms that complement Crocosmia’s more delicate sprays. Match warm dahlia tones (amber, flame, copper) for a cohesive scheme.
• Crocosmia ‘John Boots’ — pair different Crocosmia cultivars for a graduated colour display from gold through orange to red.

Frequently Asked Questions

When should I plant Crocosmia corms?

Spring, after the last hard frost — typically March or April. This gives the corms a full growing season to establish before their first winter. Container-grown plants can also be planted in early autumn in zones 7–9.

Why isn’t my Crocosmia flowering?

The three most common causes: it’s a newly planted corm (give it until the second year), the clump is overcrowded (divide in spring), or it’s not getting enough sun (needs 6+ hours daily). Occasionally, planting too deep can also delay or prevent flowering.

Do I need to lift Crocosmia corms every year?

Not in zones 7–9 — they overwinter happily in the ground. In zones 5–6, a thick mulch layer usually provides adequate winter protection. Only lift in the coldest areas or if your soil is heavy and wet in winter.

Is Crocosmia ‘George Davison’ invasive?

In garden settings, it spreads steadily but manageably by producing new corms each year. In the UK and some other regions, Crocosmia × crocosmiiflora is classified as invasive in the wild — never dump corms into green waste or natural areas. Division every 3–5 years keeps garden clumps controlled.

Can I grow Crocosmia in containers?

Yes — use a container at least 12 inches (30 cm) in diameter with good drainage. Plant corms 3 inches deep and 4 inches apart. Use a multi-purpose compost with added grit for drainage. Feed fortnightly with tomato fertiliser during summer, and water regularly. Bring containers under cover in zones 5–6 for winter. The arching flower sprays look particularly dramatic spilling over the edge of a raised container — a single large pot on a sunny terrace can be a real showstopper in late summer.

How do I stop Crocosmia spreading too much?

Regular division every 3–5 years is the most effective control. If you want to restrict spread entirely, plant in a container or use a root barrier (a buried plastic pot with the base removed works well). In garden borders, simply dig out any corms that appear beyond the intended planting area each spring — they’re shallow and easy to remove.

References

1. Royal Horticultural Society. “How to Grow Crocosmias.” RHS Gardening. [1]
2. NC State Extension. “Crocosmia × crocosmiiflora.” North Carolina Extension Gardener Plant Toolbox.
3. Missouri Botanical Garden. “Crocosmia × crocosmiiflora ‘George Davison’.” Plant Finder.
4. Gardenia. “Crocosmia × crocosmiiflora ‘George Davison’.”

References

1. Royal Horticultural Society. “How to Grow Crocosmias.” RHS Gardening.
2. NC State Extension. “Crocosmia × crocosmiiflora.” North Carolina Extension Gardener Plant Toolbox.
3. Missouri Botanical Garden. “Crocosmia × crocosmiiflora ‘George Davison’.” Plant Finder.
4. Gardenia. “Crocosmia × crocosmiiflora ‘George Davison’.”