How to grow Asparagus in New Zealand
Asparagus is a long-lived perennial vegetable: plant a bed once, wait two years, and it sends up tender spears every spring for fifteen years or more. It is usually started from bare-root crowns in late winter and does well across most of New Zealand. The secret is good soil preparation at the start and patience in the first two seasons.
📖 Our full guide: Asparagus Growing Guide NZ: Planting Crowns and Harvesting
At a glance
When to plant by region
| Region | When to plant | Regional note |
|---|---|---|
| Northland | August to November | |
| Auckland | August to November | |
| Waikato & Bay of Plenty | August to November | |
| Central North Island | August to November | |
| Wellington & Lower North Island | August to November | |
| Nelson & Marlborough | August to November | |
| Canterbury | August to November | |
| Otago & Southland | September to November | Plant Sep to Nov, once the soil can be worked. |
| Central Otago | September to November | Plant Sep to Nov, once the soil can be worked. |
Not to be confused with: Asparagus fern, climbing asparagus, bushy asparagus and bridal creeper, ornamental relatives that are National Pest Plant Accord plants in New Zealand and cannot be sold, propagated or given away. Garden asparagus (Asparagus officinalis) is not one of them.
Where to plant
Choose a sunny, well-drained spot where the bed can stay undisturbed for many years. Dig in plenty of compost or organic fertiliser before planting, and clear out perennial weeds thoroughly, as they are hard to remove once the crowns are in. Wet, heavy soil leads to crown rot, so raise the bed if drainage is poor.
- Most regions: plant crowns from August to November, as soon as the soil can be worked.
- Otago and Southland and Central Otago: plant from September to November, once the soil can be worked after winter.
Choosing a variety
Male plants give more and better spears than female plants, which put energy into red berries. Varieties sold by Kings Seeds include these.
- Mary Washington: an early heirloom with thick, dark green spears tipped with purple, and good tolerance of rust, crown rot and fusarium.
- Pacific Challenger F1: a hybrid bred in New Zealand for heavy, reliable crops of uniform spears, with resistance to phytophthora root rot.
- Pacific Purple F1: a purple hybrid with sweet, thick spears and less fibre than many green types, good raw or cooked.
How to plant crowns
- Dig blood and bone or compost through the bed.
- Dig a trench 15 to 20 cm deep.
- Make a small mound of soil every 30 to 50 cm along the base, and spread the roots of each crown over a mound.
- Cover the crowns lightly with soil and water in.
- As the shoots grow, gradually fill in the trench with soil.
- Once the trench is full, mulch thickly with compost mixed with dried grass clippings.
From seed, sow from August to November and grow the seedlings on for up to two years before planting them out in their permanent spot. Remove female plants, which carry red berries, as the males crop better.
Watering and feeding
Water regularly in dry weather, especially while the ferns are growing in summer, as this is when the crowns build up energy for next year's spears.
Feed in late winter or early spring with blood and bone or a general organic fertiliser, and give liquid feeds through the warmer months. Renew the mulch each year.
Pruning and care through the year
- In the first year, cut off any thin spears so the plant puts its energy into the roots.
- Let the ferns grow freely after harvest each year; they feed the crowns.
- Remove and compost the ferns once they yellow and die down in late autumn or winter. They come back each spring.
Harvesting
Do not cut any spears in the first year after planting crowns, and harvest lightly if at all until the second spring. From then on, cut or snap spears at ground level when they are about 20 cm tall and before the tips open, for 8 to 10 weeks each spring, then stop and let the ferns grow.
Asparagus is best eaten fresh. Stand spears upright in a little water, or wrap them in damp paper towel, and keep them in the fridge for 3 to 4 days.
Growing in pots
Asparagus is not a natural pot plant, as its crowns need deep root room. If you must, use a very deep container at least 50 cm deep and wide, and expect smaller crops than from a bed.
Using it
Steam, roast, grill or stir-fry the spears, or shave purple varieties raw into salads.
Companion planting
An asparagus bed is permanent, so companions are best planted along its edges.
Good companions
- Tomato A traditional companion; tomatoes can be grown along the edge of the bed in summer.
- Parsley A low herb for the edge of the bed that does not disturb the crowns.
- Basil A summer herb that fills space along the bed edge.
- Marigold Adds colour and attracts beneficial insects.
Keep apart
Avoid planting these close to asparagus.
Pests and diseases
Asparagus has few serious pests in New Zealand. Wet soil is the main cause of failure.
Pests to watch for
- Slugs Chewed spears and ragged holes, with silvery trails, especially in spring.
- Snails Spears grazed overnight in damp weather.
- Aphids Small insects clustered on the ferns in summer.
Diseases to watch for
- Crown rot Weak, thin spears and crowns that rot, usually in wet, poorly drained soil. Raise the bed and improve drainage.
- Rust Orange to rust-brown spots on the ferns in summer. Remove and dispose of affected ferns and choose tolerant varieties.
- Fusarium wilt Yellowing, stunted ferns and declining crowns. Buy healthy crowns and choose tolerant varieties such as Mary Washington.
Common questions
When do I plant asparagus crowns in New Zealand?
From August to November, as soon as the soil can be worked. In Otago, Southland and Central Otago, plant from September to November.
How long until I can harvest asparagus?
From crowns, wait until the second spring after planting. From seed, allow up to two more years. Cutting too early weakens the crowns.
How long do you harvest asparagus for?
For about 8 to 10 weeks each spring once the bed is established. Then stop and let the spears grow into ferns to feed the crowns for next year.
Should I remove female asparagus plants?
If you grow from seed, yes. Female plants carry red berries and male plants grow bigger and give better spears, so remove the females once you can tell them apart.
What do I do with asparagus ferns in winter?
Leave them until they yellow and die down, then cut them off and compost them, unless they had rust. Mulch the bed and feed it in late winter.
Is asparagus fern the same as garden asparagus?
No. Asparagus fern, climbing asparagus and bushy asparagus are ornamental relatives that are banned pest plants under the National Pest Plant Accord. Garden asparagus is a different species and is fine to grow.
Sources we checked: Yates NZ: How to grow asparagus; Yates NZ: Common problems of asparagus; Kings Seeds: Asparagus Mary Washington; Kings Seeds: Asparagus Pacific Challenger F1; Kings Seeds: Asparagus Pacific Purple F1; Wikipedia: National Pest Plant Accord.