How to Grow Crocosmia ‘George Davison’: Amber Montbretia That Thrives in Zones 5–9
George Davison montbretia produces amber-gold flowers every July–September in zones 5–9. Learn how to plant, divide, overwinter, and use it as a cut flower.
Most gardeners think of crocosmia as a plant that blazes orange-red through summer borders. Crocosmia ‘George Davison’ is the exception. Its flowers open amber-gold — a warm, honeyed yellow that catches late-summer light differently from the more common fiery cultivars. It is also one of the oldest named crocosmias still widely grown, with a history that stretches back to a head gardener’s walled garden in Norfolk at the turn of the twentieth century.
If you garden in USDA zones 5–9, this is a plant that returns reliably each summer, spreads into dense clumps of arching stems, and draws bees and hummingbirds from July through September. This guide covers everything: planting, seasonal care, division, overwintering by zone, and the corm biology that explains why George Davison behaves the way it does — because understanding the plant’s mechanics makes every care decision easier.
| Feature | Detail |
|---|---|
| Botanical name | Crocosmia × crocosmiiflora ‘George Davison’ |
| Common name | Montbretia ‘George Davison’ |
| Family | Iridaceae (iris family) |
| Height / Spread | 75–90 cm (30–36 in) / 30–45 cm (12–18 in) |
| Bloom time | July to September |
| Flower color | Amber-gold / honey-yellow |
| USDA Zones | 5–9 (with winter protection in Zone 5) |
| RHS hardiness | H5 (hardy to −15°C / 5°F) |
| Light | Full sun preferred; partial shade tolerated |
| Soil | Moist, well-drained, humus-rich; pH 6.0–8.0 |
| Wildlife | Bees, butterflies, hummingbirds |
| Deer / rabbit resistant | Yes |
The Story Behind the Name
Crocosmia carries two histories at once — the hybrid that created it, and the man who first developed it for British gardens.
The hybrid itself, Crocosmia × crocosmiiflora, was created in 1880 by Victor Lemoine, a French nurseryman who crossed two South African species: Crocosmia aurea, which had arrived in European plant collections around 1847, and C. pottsii, which followed about twenty years later. Lemoine named the result Montbretia × crocosmiaeflora, after Antoine François Cocquebert de Montbret — a young French botanist who died in Cairo in 1801 before seeing any of his fieldwork published. The common name montbretia has stuck ever since. Kew’s Plants of the World Online records this hybrid as native to the Eastern Cape and KwaZulu-Natal in South Africa, now naturalised in more than forty countries worldwide.
George Davison enters the story around 1900. He was head gardener at Westwick Hall in Norfolk, and is generally regarded as the first Englishman to breed crocosmia systematically. The cultivar bearing his name earned an RHS Award of Merit in 1902. He went on to produce eleven more hybrids before shifting his attention to apple breeding in 1912.
By the 1920s, hundreds of crocosmia cultivars existed across British nurseries and private gardens. Then World War II arrived. The wartime “Dig for Victory” campaign converted ornamental gardens to food production, and the combination of wartime disruption and changing fashion erased roughly three-quarters of those cultivars entirely by the war’s end, according to Pacific Horticulture’s chronicle of the genus. ‘George Davison’ is among the survivors — one of a small number of historic cultivars still available today. David Fenwick, former curator of the British National Collection of Crocosmia, describes it as “highly recommended” — a considered endorsement from someone who has grown hundreds of varieties side by side.
How the Corm Works — and Why It Matters for Your Garden
George Davison does not grow from a bulb. It grows from a corm — a solid, swollen stem base that stores the energy reserves the plant draws on each spring. Understanding how corms behave explains almost every quirk of this plant’s performance in the garden.
Each growing season, a new corm forms directly on top of the previous one. These stack into vertical chains: the youngest, smallest corm sits at the top; the oldest, largest corm is buried deepest. As new chains form at the edges of the clump, the plant spreads outward into the dense swathes montbretia is known for. The lowermost corm in each chain is anchored by contractile roots — specialised roots that physically shorten after elongating, pulling the oldest corm incrementally deeper into the soil year after year.
This chain structure explains why congested clumps stop flowering well. When corm chains pack together without room to develop properly, the newest corms — the productive ones at the top of each string — form small and under-resourced. Flowering declines noticeably. Division solves this by resetting the available space: you lift the chains, keep only the top two corms from each string (the most recently formed and energy-rich), and replant them with room to build fresh chains.
‘George Davison’ is described by experienced growers as “rampant in the right conditions.” That is not a warning — it is a description of efficient corm multiplication. In a sunny, well-drained border, this cultivar expands steadily and fills gaps reliably. In a small garden or containers, more frequent division keeps the spread manageable.
One botanical footnote: the genus name Crocosmia comes from the Greek krokos (saffron) and osme (odor). Dip the dried leaves or flowers in hot water and you will notice a faint saffron-like scent — the characteristic that gave the genus its name and distinguishes it from other summer perennials in Iridaceae.
Choosing the Right Site
Light
Full sun is the primary requirement — at least six hours of direct sunlight daily for reliable flowering. Partial shade (two to four hours) is tolerated but produces lighter flowering and fewer stems. In zones 7–9, afternoon shade extends individual flower longevity by shielding blooms from peak heat, so a morning-sun position works particularly well in the warmest gardens.
Soil
George Davison is more flexible about soil type than many perennials. The RHS confirms it performs well in chalk, clay, loam, and sandy soils, provided drainage is adequate. Moist but well-drained is the target: consistently moist but never waterlogged. NC State Extension notes that the plant does not tolerate clay that holds standing water, and prolonged dry soil also stresses the corms. Target pH is 6.0–8.0 — broadly neutral, with no acidic amendment needed.
Waterlogged winter soil is the greatest risk, particularly in zones 5–6. Wet conditions at low temperatures cause corm rot at temperatures that dry cold alone would not reach. If your soil is heavy clay, incorporate coarse horticultural grit when planting to improve winter drainage.
How to Plant Crocosmia ‘George Davison’
When to Plant
Plant dormant corms in spring, after the last frost date and once soil temperature reaches at least 10°C (50°F). In zones 5–6 this typically means late May or early June. Corms planted in cold soil sit dormant rather than establishing, and the delay carries through the entire growing season.
Preparing the Bed
Dig in a generous amount of well-rotted compost before planting. This improves drainage in clay soils, adds water retention in sandy soils, and provides the organic matter the corms draw on during their first season. No additional fertilizer is needed at planting time in reasonably fertile soil.
Planting Depth and Spacing
Plant each corm at approximately three times its own depth — typically 7–10 cm (3–4 inches) for standard-sized George Davison corms. Place the slightly pointed end upward. Space corms 10–20 cm (4–8 inches) apart. Closer spacing produces a faster-filling clump but requires more frequent division; wider spacing delays the dense swathe effect but reduces maintenance in the early years.
Plant in groups of at least five to seven corms for effective display. A single corm produces one modest stem. A group produces the multi-stemmed arching clump that makes George Davison effective in the middle of a border or as a repeated element along a path edge.
Watering, Feeding, and Seasonal Care
Watering
Consistent moisture through the growing season matters more than irrigation volume. Aim for roughly 2.5 cm (one inch) of water per week, either from rainfall or supplemental irrigation. NC State Extension notes that crocosmia “does not like to dry out” — prolonged drought reduces flowering and stresses the developing corms. Established clumps in their third year or beyond handle brief dry spells better than freshly planted corms.
Feeding
Ground-grown plants in moderately fertile soil do not need supplemental feeding. The RHS is explicit on this point: in-ground crocosmias in good soil require no fertiliser. If your soil is poor or very sandy, a balanced slow-release fertilizer applied in early spring as growth emerges is sufficient.
Container plants are different. Pots restrict root access to soil nutrients, and the regular watering required flushes nutrients out faster than in open borders. Apply a high-potassium liquid fertilizer — tomato food works well — at half strength every two weeks throughout summer. High-potassium feed promotes flower production over leafy growth, which is what you want from a flowering perennial in a pot.
Managing Foliage and Spent Flowers
Remove spent flower stems once all florets have faded, redirecting energy toward corm development rather than seed production. Do not cut the foliage back immediately after flowering. The sword-shaped leaves continue photosynthesising through autumn, recharging the corms for next year. Cutting them back early is the fastest way to weaken the following season. Cut back dead foliage in late autumn after the first frost, or leave it standing through winter for insect shelter and tidy in early spring before new shoots appear.
Seasonal Care Calendar
| Month | Task |
|---|---|
| March–April | Plant new corms; divide congested clumps before new growth emerges |
| May–June | Water during dry spells; begin fortnightly feeding for container plants |
| July–September | Water consistently; continue fortnightly feeding for containers; harvest cut stems |
| October | Cut spent flower stems; taper irrigation; apply autumn mulch in zones 5–7 |
| November–February | Dormant; check stored corms monthly if lifted for winter |
Dividing George Davison for Continued Flowering
Divide congested clumps every three to five years to maintain flowering vigour. NC State Extension recommends a shorter cycle — every two to three years — for maximum flower production. The signal that division is overdue: abundant foliage and noticeably fewer flowers compared to previous seasons. Our guide to dividing perennials covers the general principles if you are new to the process.
Timing is early spring, just before new growth emerges, when corms are dormant and the chain structure is easiest to separate cleanly. This gives divided sections the entire growing season to re-establish before winter.
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- Work a border fork into the soil at the outer edge of the clump and lift the entire root mass, working inward to avoid severing corm chains.
- Gently pull corm chains apart by hand — they separate along natural joining points.
- From each chain, keep only the top two corms. These are the youngest and most energy-rich. Discard or compost the older lower corms, which have already flowered multiple times and contribute little going forward.
- Replant selected corms immediately at 10–20 cm spacing and the same depth as before.
- Water in thoroughly and mulch lightly if dividing in early spring when frost is still possible.
Seed propagation is not practical for this cultivar. Crocosmia × crocosmiiflora rarely sets viable seed, and any seedlings that do germinate will not come true to type — the amber-gold flower color that defines George Davison cannot be reliably reproduced from seed. Division is the only method that preserves the cultivar.
Overwintering George Davison: A Zone-by-Zone Guide
Zones 7–9
No action required beyond tidying. George Davison is fully hardy in the ground across zones 7–9. Cut back dead foliage in late autumn or early spring. A light mulch of compost is beneficial but not critical. Corms survive and flower reliably year after year without intervention.
Zone 6
Apply a mulch of 10–15 cm (4–6 inches) of garden compost, straw, or shredded leaves after the first hard frost. This insulates the soil, prevents freeze-thaw cycling from heaving corms upward, and moderates temperature swings through the coldest months. Well-drained soil is essential: the primary killer in zone 6 is wet winter soil combined with cold, not cold alone.
Zone 5 (Borderline Hardy)
Zone 5 is the outer edge of in-ground reliability for George Davison. Two approaches work:
Option 1 — In-ground with heavy mulch: Apply 15–20 cm (6–8 inches) of straw or shredded leaves after the first frost. Choose a sheltered south-facing spot near a wall or fence, where temperatures run 2–3°C warmer than open ground. This succeeds in most zone 5 winters but is not guaranteed in extreme seasons. Critically, the soil must drain freely — wet conditions at −10°C will kill corms that dry cold alone would not.
Option 2 — Lift and store: After the first frost kills the foliage, cut stems back to 10 cm, lift corm chains carefully, allow them to dry for two or three days, then store in paper bags with barely-moist peat or vermiculite at approximately 4°C (40°F) — a cool garage or basement shelf works well. Check monthly for shrivelling (mist lightly if so) or rot (remove affected corms immediately). Replant in late spring once soil warms above 10°C.
If your zone 5 winters are reliably cold but dry, Option 1 often succeeds. If winters are cold and wet — common in parts of the Pacific Northwest and upper Midwest — Option 2 is more dependable.
Zone 4 and Below
Lift and store annually. Treat like gladiolus corms. Replant each spring once frost danger has fully passed and soil has warmed.
Pests and Problems
George Davison is described by the RHS as “generally pest-free and generally disease-free” — accurate for most garden situations. The table below covers the problems that do arise:
| Symptom | Likely Cause | Solution |
|---|---|---|
| Fine webbing on leaves; stippled, bronze-tinted foliage | Red / two-spotted spider mites — favour hot, dry conditions | Hose down forcefully with water weekly; keep soil consistently moist; drought stress invites outbreaks |
| Abundant foliage, very few flowers | Overcrowded corms — newest corms too small to flower | Divide in early spring; replant only the top two corms from each chain |
| Poor flowering despite space and recent division | Insufficient sun or chronically dry soil | Relocate to a site with 6+ hours direct sun; irrigate consistently through the growing season |
| Mushy corms or rotting crowns | Waterlogged winter soil | Improve drainage with grit or raised planting; lift and store in wet-winter zones |
| Stunted spring growth; purple tinge to young leaves | Corms planted in cold soil | Wait until soil reaches 10°C (50°F) before planting; delayed planting is better than cold-stressed establishment |
| Yellowing foliage in late summer or early autumn | Natural senescence as corms shut down for dormancy | No action needed — do not cut back early; let leaves yellow fully before removal |
Using George Davison: Companions, Cut Flowers, and Wildlife
Companion Planting for a Yellow Crocosmia
The amber-gold of George Davison contrasts more sharply with blue and purple perennials than with other warm-toned plants. The most effective combinations for this specific cultivar use complementary cool tones to make the yellow pop:
- Agapanthus — blue and violet umbels above strap-shaped foliage provide a strong complementary contrast that works across the entire late-summer bloom window both plants share.
- Helenium — sharing the late-summer bloom period and warm tones, helenium and George Davison together extend the display from July well into September.
- Salvia nemorosa cultivars — blue-purple spikes planted between clumps of amber montbretia produce a classic complementary scheme that works in borders of almost any size.
- Ornamental grasses such as Stipa tenuissima or Calamagrostis × acutiflora — fine, airy texture contrasts with George Davison’s upright sword leaves and arching stems, adding movement without competing visually.
- Kniphofia — architectural red-hot pokers alongside amber montbretia create bold late-summer drama; both share similar sun and drainage preferences.
- Dahlias — dark-leaved or bronze-foliaged dahlias behind George Davison intensify the amber tones; tuber-care timing aligns conveniently with corm management.
Cut Flower Use
George Davison’s arching stems make it one of the better crocosmias for cutting. Each stem carries florets that open progressively from the bottom upward, so a stem cut when the lower two or three florets are open continues revealing new flowers in the vase for up to seven to fourteen days. Our cut flower guide covers general conditioning technique. For crocosmia specifically: cut stems in the morning, place immediately in lukewarm water with floral preservative, and allow to hydrate for two to four hours before arranging. Remove any foliage below the waterline to prevent bacterial buildup.
Wildlife Value
George Davison is a reliable pollinator plant for the mid-to-late summer gap when many spring perennials have finished. Bees and butterflies visit regularly. It does attract hummingbirds, but with a nuance worth understanding: crocosmia’s curved corolla tube evolved in co-adaptation with South African sunbirds, whose curved bills fit the flower’s shape precisely. North American hummingbirds have only slightly curved bills — an anatomical mismatch that means they visit crocosmia less frequently than they do straight-tubed native flowers like cardinal flower or coral honeysuckle. The plant contributes genuine value to a wildlife-friendly garden; it simply will not draw hummingbirds with the same reliability as native wildflowers.
The shiny black seeds that follow the flowers attract songbirds in autumn if left in place rather than deadheaded. George Davison is also deer and rabbit resistant — a practical advantage in gardens where browsing pressure is heavy.
How George Davison Compares to Other Yellow Crocosmias
If you are weighing George Davison against other yellow-toned montbretias, this comparison covers the most widely available options. See also our profile of Crocosmia ‘John Boots’ for a compact yellow-orange alternative suited to smaller spaces.
| Cultivar | Height | Flower Color | Bloom Time | Best For |
|---|---|---|---|---|
| ‘George Davison’ | 75–90 cm | Amber-gold | July–Sept | Bold mid-border swathe; historic 1902 cultivar; vigorous spreader with proven track record |
| ‘Solfatare’ | 60–75 cm | Apricot-yellow | Aug–Sept | Smoky bronze foliage contrast; less vigorous; suits smaller spaces and containers |
| ‘John Boots’ | 60–75 cm | Yellow-orange | July–Aug | Compact habit; reliable choice for small borders and mixed pots |
| ‘Star of the East’ | 60–75 cm | Apricot-orange | Aug–Sept | Larger individual florets; slightly warmer tone; good cut flower |
| ‘Lucifer’ | 90–120 cm | Scarlet-red | July–Aug | Maximum height and impact; upward-facing flowers; the benchmark contrast choice alongside yellows |
If you want a contained yellow for a small border or front-of-border position, ‘Solfatare’ or ‘John Boots’ spreads less aggressively. If you want a vigorous, historically significant mid-border performer with genuine amber tones and a 120-year pedigree, George Davison is the stronger choice.
Frequently Asked Questions
Is Crocosmia ‘George Davison’ invasive?
In England and Wales, all Crocosmia × crocosmiiflora cultivars are listed as Schedule 9 species under the Wildlife and Countryside Act — it is an offence to plant them or cause them to grow in the wild. In US gardens across zones 5–9, George Davison spreads vigorously by corm multiplication but is manageable with division every three to five years. In zones 9 and above, or in mild maritime climates, monitor border edges and divide more frequently to keep spread in check.
Why isn’t my George Davison flowering?
The two most common causes are overcrowded corms and insufficient sun. Overcrowding suppresses the newest corms: divide in early spring and replant only the top two corms from each chain. If the plant has adequate sun and space but still flowers poorly, check planting depth — corms planted too shallow may not establish properly. Newly planted corms can also take two to three seasons to reach full flowering potential.
Can I grow George Davison in containers?
Yes, with a few adjustments. Use a pot at least 30 cm (12 inches) deep to accommodate the developing corm chains, with drainage holes. Water consistently — pots dry out faster than borders. Feed with high-potassium liquid fertilizer every two weeks throughout summer. In zones 5–6, move pots into a sheltered frost-free location for winter rather than leaving them outdoors exposed.
Is George Davison toxic to cats or dogs?
Mildly. The above-ground foliage and flowers can cause mild gastrointestinal upset if eaten in significant quantities. The corms are more irritating and may cause more pronounced vomiting. It is not considered life-threatening, but households with pets that habitually chew plants should plant with awareness and keep lifted corms out of reach during division and storage.
Sources
- RHS — Crocosmia × crocosmiiflora ‘George Davison’: Plant Profile
- RHS — How to Grow Crocosmia
- NC State Extension — Crocosmia (Montbretia) Plant Toolbox
- NC State Extension — Crocosmia × crocosmiiflora Plant Toolbox
- Pacific Horticulture — Wildly Successful: Crocosmia × crocosmiiflora
- Kew Plants of the World Online — Crocosmia × crocosmiiflora
- Lemon Bay Conservancy — Should You Plant Crocosmia as a Hummingbird Flower?
- Old House Gardens — George Davison Crocosmia
