Sale
Sold out
Hardy spring-flowering corm
Iridaceae
Naturalizing blue crocus for early-spring bloom
Yellow Mammoth Crocus (Crocus vernus)
Crocus vernus Yellow Mammoth
Product code : VAN-141-150-01
Yellow Mammoth crocus is a hardy 10 cm spring crocus supplied as 10 corms. Its bright yellow flowers, accented by contrasting centres, open very early in sunshine. Plant corms in fall, 5 cm deep and 5 cm apart, in loose, freely drained soil. Suitable for Zones 3 to 8, it thrives in rock gardens, borders, lawns, and open woodland. Let the narrow foliage yellow after flowering so it can replenish the corms. Where winter drainage is reliable and the soil never remains waterlogged, it returns and gradually develops into a natural-looking colony that becomes more generous over time. reliably in gardens
- Quantity
- 10 corms
- Exposure
- Full sun to partial sun
- Life cycle
- Naturalizing perennial
- Hardiness
- Zones 3 to 8
Discover the plant
Common nameYellow Mammoth spring crocus
FamilyIridaceae
GenusCrocus
Speciesvernus
CultivarYellow Mammoth
TypeHardy spring-flowering corm
Botanical nameCrocus vernus Yellow Mammoth
Reproducible seedsYes
Yellow Mammoth crocus (Crocus vernus) opens large bright-yellow cup-shaped flowers in early spring, highlighted by orange stamens and especially luminous in sunshine. Blooms expand on clear days and close at night or when skies become cloudy. Narrow dark-green foliage marked by a silver stripe remains discreet beneath the flowers. At 10 to 15 cm tall, this large-flowered crocus creates an energetic accent without hiding neighbouring plants. The Van Noort retail package contains 10 corms. Hardy from Zone 3, it returns reliably in well-drained soil and can gradually form a cheerful colony among later-emerging perennials.
Plant the 10 corms from September through November before the ground freezes, setting them 8 cm deep and 5 to 8 cm apart. Choose full sun or light shade beneath deciduous trees in light, fertile soil that stays fresh in spring and drains freely. Position each corm pointed end upward, water after planting, then let seasonal rainfall maintain moderate moisture while roots develop. Avoid waterlogged hollows, compact clay, and strongly nitrogenous fertilizers. A thin layer of mature compost is generally sufficient to support flowering without encouraging excessive foliage. Mark the group so later digging never damages dormant corms.
Bright yellow crocus stands out in rock gardens, borders, naturalized lawns, gravel gardens, open woodland, and containers prepared in fall. Gather all 10 corms in one irregular island to create a yellow drift visible as snow melts. Pair it with violet crocuses, white snowdrops, blue reticulata iris, and small daffodils. Early flowers provide pollen and nectar to the first active bees on mild days. After flowering, allow foliage to yellow completely so corms can replenish their reserves. Mow only after leaves disappear, divide overcrowded colonies during dormancy, and promptly replant firm cormlets at their recommended depth in freshly loosened, freely drained soil.
Planting guide
Plant well.Grow beautifully.
Planting depth
8 cm (3 in)
Spacing / density
5 to 8 cm (2 to 3 in)
Best planting time
September to November, before the ground freezes
Propagation
Corms and separation of cormlets during dormancy
Growing method
Plant Yellow Mammoth crocus in fall from September through November before the ground freezes. Choose full sun or partial sun, including beneath deciduous trees that remain open in early spring. Loosen soil to 15 cm and incorporate a small amount of mature compost; add fine gravel where drainage is slow. Set corms 5 cm deep with pointed ends upward and leave 5 cm between them. Group all 10 corms for a visible drift. Water once after planting to settle the soil, then allow normal fall and spring precipitation to provide moisture. Avoid hollows where water collects during thaw periods. In spring, do not tread on emerging shoots and use only a gentle bulb fertilizer if soil is poor. After flowering, let the narrow leaves yellow completely because they rebuild corm reserves. In lawns, delay mowing until foliage disappears. Divide only colonies that have become crowded, after leaves are dry and the corms are dormant. This practice respects the natural cycle of spring crocus keeps corms healthy in drained soil and encourages reliable white flowers as the first mild days return without requiring complicated care This practice respects the natural cycle. carefully
Soil and care
The right care,at the right time.
Soil pH
6.0 to 7.0
Minimum temperature
Approximately −34°C in freely drained soil, corresponding to Zone 3
Care level
Moderate
Watering
Water once after fall planting to settle soil around the corms. Normal precipitation is generally sufficient until spring. During flowering and leaf growth, maintain light moisture if weather is unusually dry without saturating the ground. Reduce irrigation as foliage yellows and keep the area relatively dry through summer dormancy. Check containers more often while always allowing excess water to drain freely. This practice respects the natural cycle of spring crocus keeps corms healthy in.
Soil type
Light, humus-rich, freely drained soil is ideal, especially sandy loam amended with a little mature compost. The ground must release fall rain and spring meltwater quickly to prevent corm rot. In clay, create a slight mound and incorporate fine gravel. Avoid fresh manure, waterlogged hollows, and thick mulch that keeps the emerging crowns wet. This practice respects the natural cycle of.
Fertilization
Incorporate mature compost before planting. When shoots reach 8 cm (3 in), apply balanced slow-release fertilizer or a half-strength liquid feed. Repeat once as buds begin forming. Avoid excess nitrogen, which promotes foliage and weak flowers at the expense of flowers and the corm’s stored energy. Stop feeding after bloom so foliage can mature naturally and corms can enter dormancy with firm, well-ripened tissues.
Moisture
Maintain moderate, even moisture through establishment, active growth, and flowering without leaving corms in saturated soil. Rapid drainage is essential for winter hardiness, especially in Zone 3. Reduce irrigation as foliage yellows. Light mulch conserves summer moisture, but keep it away from emerging shoots to preserve airflow and prevent crown rot after prolonged rain or repeated winter thaws in Quebec gardens.
Seasonal care
In fall, loosen and drain the site before setting corms 5 cm deep. Water after planting and mark the group to prevent disturbance. In winter, do not let a saturated container or accumulated meltwater create prolonged waterlogging; garden corms nevertheless remain in place throughout Zones 3 to 8. In early spring, gently remove debris covering new shoots and watch for slugs. Water only when spring is unusually dry. During flowering, avoid pesticides to protect the first visiting insects. After bloom, leave every leaf in place until it becomes yellow and dry. Do not tie foliage or mow a lawn too early. As dormancy begins, remove dead leaves. Every three to five years, if flowering declines, lift the dormant colony, separate firm cormlets, and replant them promptly at the recommended depth. Finish with a thin surface layer of compost without digging deeply around established corms. This practice respects the natural cycle of spring crocus keeps corms healthy in drained soil and encourages reliable white flowers as the first mild days return without requiring complicated care This practice respects the natural cycle of spring crocus keeps corms healthy in drained soil and encourages reliable white flowers as the first mild days return without requiring complicated care This practice respects the natural cycle of spring crocus keeps corms healthy in drained. with care
Container growing
A garden,within reach.
Recommended pot size
35 to 10 cm (14 to 16 in) wide and at least 8 cm (3 in) deep for 10 corms
For 10 corms, choose a container at least 25 cm wide and 20 cm deep with several drainage holes. Fill it with container mix loosened with perlite or fine gravel. In fall, set corms 5 cm deep and about 5 cm apart, then water once. Keep the pot outdoors in a cold, bright position protected from excessive rain; corms require winter chilling to flower. In very exposed areas, place the container against a wall or inside an unheated cold frame and insulate its sides, without moving it into a warm room. In early spring, return it to full light and keep the mix lightly moist, never saturated. After flowering, continue moderate watering until leaves have yellowed completely. Then stop watering during summer dormancy. Corms may remain in the pot while drainage stays open; repot and separate crowded groups the following fall. This practice respects the natural cycle of spring crocus keeps corms healthy in drained soil and encourages reliable white flowers as the first mild days return without requiring complicated care This practice respects the natural cycle of spring crocus keeps corms healthy in drained soil and encourages reliable. reliably
Bloom and dimensions
Its place,in your garden.
Mature height
10 to 15 cm (4 to 6 in)
Width / spread
10 to 15 cm (4 to 6 in) after naturalizing
Flower color
Bright yellow, orange stamens
Foliage color
Green
Foliage type
Deciduous, strap-like, and sword-shaped
Growth rate
Moderate
Growth habit
Low, upright, and naturalizing
Fragrance
Light or absent; grown primarily for colour
Bloom period
In early spring, bright yellow cup-shaped flowers open in sunshine and reveal bright contrasting centres. Each plant remains low at about 10 cm and gives its strongest display in compact groups. Blooms often close during dull weather and reopen when sunlight returns. Fall planting in drained soil encourages reliable flowering and gradual naturalizing. This practice respects the natural cycle of spring crocus keeps corms healthy in drained.
Harvest
March to April. Allow the flowers to fade naturally to encourage bulb multiplication and naturalization.
Garden associations
In goodcompany.
Companion plants
Snowdrops, reticulata iris, squill, glory-of-the-snow, and small daffodils share early bloom and a preference for drained soil. Hellebores add volume behind crocuses without hiding them in early spring. Later, hostas, ferns, and hardy geraniums can conceal yellowing foliage. Avoid bog plants, smothering groundcovers, and perennials that require constant summer irrigation in the same position. This practice respects the natural cycle of spring crocus keeps corms healthy in drained soil and encourages reliable white flowers as the first mild days. nearby
Frequently asked questions
Your questions,answered.
When and how should Yellow Mammoth crocus corms be planted?
Plant corms from September through November before the ground freezes. Choose a full-sun or partial-sun position where soil drains rapidly. Set each corm 5 cm deep and 5 cm from the next, with the pointed end upward. If orientation is unclear, place it on its side and the shoot will find the light. Group all 10 corms for a visible drift rather than scattering them. Water once after planting, mark the position, and avoid excessive irrigation afterward. Roots develop in fall and flowers appear in early spring following the natural winter chilling period. This practice respects the natural cycle of spring crocus keeps corms healthy in drained soil and encourages.
Why does Yellow Mammoth crocus produce leaves but few flowers?
Poor flowering can result from dense shade, waterlogged soil, corms planted too shallowly, or foliage removed before maturity. Give the group several hours of early-spring light and make sure meltwater never remains around it. Let every leaf yellow completely after flowering because it replenishes the corm. Avoid high-nitrogen fertilizers that mainly promote leaves. If an old colony becomes very crowded, lift it during summer dormancy, separate firm cormlets, and replant them 5 cm deep in refreshed, drained soil. This practice respects the natural cycle of spring crocus keeps corms healthy in drained soil and encourages reliable white flowers as. reliably
Must the corms be lifted for winter in Quebec?
No. Yellow Mammoth crocus is intended to remain in the ground through winter in Zones 3 to 8 where drainage is good. Plant it at the recommended depth and avoid hollows where water collects during thaws. A thin mulch layer can moderate temperature in an exposed site, but remove it gradually as shoots emerge. Containers freeze more deeply, so place the pot against a wall, insulate its sides, or use an unheated cold frame. Do not move corms into a warm room because they need a cold period. Lift them only to divide a crowded colony or correct poor drainage. This practice respects the natural cycle of spring.
When can a lawn planted with Yellow Mammoth crocus be mown?
Wait until flowers have faded and every leaf has turned yellow and dry, usually several weeks after flowering. Green foliage manufactures the reserves needed for crocuses to return the following spring, so early mowing gradually reduces bloom. Set the first cut fairly high and avoid scalping the soil. In a heavily used lawn, mark groups or position them near edges to limit trampling. Do not apply herbicide to active leaves. Once dormancy begins, the lawn can resume normal maintenance until the next emergence. This practice respects the natural cycle of spring crocus keeps corms healthy in drained soil and encourages.
Is Yellow Mammoth crocus edible or safe to ingest?
No. Crocus vernus Yellow Mammoth is grown solely as an ornamental and must not be confused with saffron crocus, Crocus sativus. Corms, leaves, and flowers are not intended for consumption. Keep packages and corms beyond the reach of children and digging pets. Wear gloves if your skin is sensitive and wash tools after planting. If a person or animal swallows any part and develops drooling, vomiting, diarrhea, or discomfort, promptly contact a poison centre, medical professional, or veterinarian and provide the name Crocus vernus. Never use ornamental crocus flowers as a garnish or attempt to harvest their stamens for food, tea, seasoning, or decoration.
Wildlife and pets
Life,around your plants.
Reported toxicity
Yes
Supporting wildlife
Very early flowers can provide pollen and nectar to bees and other insects active on the first mild days. Their contribution is most useful when several corms bloom together and no pesticides are applied. Combine them with snowdrops, hellebores, and squill to extend available forage. The flowers are not an important food source for birds or hummingbirds.
For planting your bulbs
The right extras.Right here.
Bulb planters and planting tools
Shop the collection
Soils and amendments for bulbs
Shop the collection
