Crop type: Asparagus
Asparagus officinalis ‘Connover's Colossal’
Common name: Asparagus ‘Connover's Colossal’
Crop slug: asparagus
This Allotment Pro editorial draft summarises the cited RHS cultivar profile. Check the source and adjust cultivation decisions for local conditions.RHS cultivar profile
1 - Overview
‘Connover's Colossal’ is an upright, deciduous asparagus grown for edible bright-green spears with purple tips from spring into early summer. Once harvesting stops, the crowns send up tall, branched stems carrying airy, feathery green foliage.
This established cultivar has an RHS Award of Garden Merit. Its combination of large crops, strongly coloured spear tips and an upright summer habit makes it a distinctive choice for a permanent asparagus bed.
2 - Size
- Ultimate height
- 1–1.5 metres
- Ultimate spread
- 0.1–0.5 metres
- Time to ultimate size
- 2–5 years
Allow enough vertical space for mature summer stems up to about 1.5 metres tall. The clump remains comparatively narrow, but the branched foliage can spread as the season progresses and may need support.
3 - Growing conditions
- Suitable soils
- Chalk, clay, loam and sand
- Moisture
- Well-drained
- Soil pH
- Alkaline or neutral
Choose a permanent bed where excess water can drain freely. Raised beds are suitable where the natural ground is heavy or drainage is unreliable.
4 - Position and hardiness
- Light
- Full sun
- Aspect
- South- or west-facing
- Exposure
- Sheltered
- Hardiness
- H4 — hardy through most of the UK once established, although the emerging spring spears remain vulnerable to frost
Site the crowns in a warm, sunny position protected from strong winds. Avoid frost pockets because late cold can damage the tender edible spears even though the established perennial crown is hardy.
5 - Colour and seasonal interest
| Season | Flowers | Foliage | Fruit |
|---|---|---|---|
| Spring | — | Green | — |
| Summer | — | Green | — |
| Autumn | — | Green | — |
The crop's most recognisable colour is in its bright-green spring spears with purple tips. An em dash means the RHS profile does not state a colour for that field and season.
6 - Botanical details
- Family
- Asparagaceae
- Native to Great Britain and Ireland
- No
- Foliage
- Deciduous
- Habit
- Columnar upright and spreading branched
- Name status
- Accepted
Genus
Asparagus includes evergreen and deciduous perennials or subshrubs, sometimes climbing, with tuberous rootstocks. Their stems carry small scale-like leaves and larger leaf-like phylloclades; small white or pinkish flowers may be followed by red berries.
Safety
The young spears are edible when cooked. Wear gloves when picking because contact may cause a skin allergy, and do not eat the harmful fruits.
7 - How to grow
Cultivation
Plant crowns in well-drained soil or a raised bed, choosing a site outside frost pockets. Let young crowns establish before cutting, then leave the feathery summer growth intact after harvest so it can replenish the plant.
Propagation
Propagate by crowns. Seed propagation is possible but is not recommended because seedlings take longer to mature and may not be male plants, which generally crop more strongly.
Suggested locations
- Wildlife gardens
- Sunny, sheltered edible gardens
- Free-draining raised vegetable beds
Pruning
Cut the foliage down to soil level in autumn after it has yellowed.
Pests
‘Connover's Colossal’ may be susceptible to asparagus beetle, slugs and snails. Inspect emerging spears and summer foliage for feeding damage.
Diseases
Possible problems include foot and root rots and violet root rot. Good drainage is particularly important for reducing conditions that favour root decay.