How to grow Alyssum in New Zealand
Sweet alyssum is a low, spreading annual that covers itself in tiny honey-scented flowers in white, pink, violet or cream. It is one of the most useful flowers in a vege garden, because hoverflies, bees and other beneficial insects feed on it, and hoverfly larvae eat aphids. It is easy from seed and often self-sows to fill gaps year after year.
📖 Our full guide: How to Grow Alyssum in New Zealand
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| Northland | September to April | |
| Auckland | September to April | |
| Waikato & Bay of Plenty | September to April | |
| Central North Island | September to April | |
| Wellington & Lower North Island | September to April | |
| Nelson & Marlborough | September to April | |
| Canterbury | September to March | Make the last sowing in Mar so the crop is ready before winter growth stops. |
| Otago & Southland | October to March | Start spring sowings in Oct under a cloche or frost cloth, as frosts run to late October. Make the last sowing in Mar so the crop is ready before winter growth stops. |
| Central Otago | October to February | Start spring sowings in Oct under a cloche or frost cloth, as frosts run into early November. Make the last sowing in Feb so the crop is ready before winter growth stops. |
Where to plant
Grow alyssum in full sun to part shade in well-drained or sandy soil. It makes a neat edging for beds and paths, fills gaps between pavers, and works well in pots and hanging baskets. Dot it among vegetables and under fruit trees to bring in the beneficial insects that help keep aphids down. Kings Seeds sells a white alyssum specifically for sowing in orchards and vineyards for this reason.
- Northland, Auckland, Waikato and Bay of Plenty, the central North Island, Wellington and Nelson and Marlborough: sow from September to April.
- Canterbury: sow from September to March, with the last sowing in March so plants are flowering before winter.
- Otago and Southland: sow from October to March, starting under a cloche or frost cloth, as frosts run to late October.
- Central Otago: sow from October to February, with early sowings under cover, as frosts can run into early November.
Choosing a variety
- Carpet of Snow: the classic low mat of fragrant white flowers, for edging and gaps between pavers.
- Royal Carpet: a deep violet-purple form with the same sweet scent.
- Mixes such as Magic Circles and Painter's Palette give soft pinks, lilacs and white.
How to plant
- Loosen the soil and rake it to a fine surface, working in a little compost or organic plant food.
- Scatter the tiny seed thinly where it is to flower, or in trays of seed raising mix.
- Barely cover the seed, as it germinates faster and more evenly when only just covered, then firm it down and water gently.
- Keep the surface moist until seedlings appear in 7 to 14 days.
- Transplant tray-raised seedlings once they are about 4 cm tall, 10 to 20 cm apart, and water in well.
Watering and feeding
Keep seedlings moist while they establish. Once growing, alyssum copes with dry spells, but it flowers for longer if watered in dry weather. Mulch lightly, keeping mulch clear of the stems.
Feed now and then with a flower fertiliser; pots benefit from a liquid feed every week or two.
Pruning and care through the year
- When flowering slows, shear the plants back lightly to bring on a fresh flush of flowers.
- Leave a few plants to set seed if you want them to self-sow and come back next season.
Harvesting
There is nothing to pick for the kitchen. Plants flower about 60 to 80 days after sowing and keep going for months. Shear them back lightly when they get straggly.
Growing in pots
Alyssum suits pots, window boxes and hanging baskets at least 15 to 20 cm wide and deep, filled with a quality potting mix. Press the seed lightly into the surface, keep it moist until it comes up, and feed every week or two once it is growing.
Companion planting
Alyssum is a companion plant in its own right: it feeds the hoverflies and other beneficial insects that help control aphids on nearby crops.
Good companions
- Lettuce A low edging of alyssum brings in hoverflies, whose larvae eat the aphids that colonise lettuce.
- Brassicas Planted among cabbages and broccoli, it supports beneficial insects that help keep aphids in check.
- Beans Its low growth does not compete, and it draws pollinators and aphid predators.
- Strawberry It edges a strawberry bed well and draws in pollinating insects.
Pests and diseases
Alyssum is easy and rarely seriously troubled.
Pests to watch for
- Slugs Seedlings and young plants chewed, with silvery trails.
- Snails Large ragged holes in leaves and silvery trails, worst in damp weather.
- Mealybug Distorted new growth with a white, cottony substance where leaves join the stem.
Diseases to watch for
- Downy mildew Yellow patches on the upper leaf with grey or purplish fuzz underneath, worst in cool, humid weather.
Common questions
When should I sow alyssum in New Zealand?
From September to March in most of the country. In the south, start in October under a cloche or frost cloth, and finish by March, or by February in Central Otago.
Does alyssum come back every year?
It is an annual, but it self-sows readily, so new plants often come up in the same spot the next season if you leave some flowers to set seed.
Why plant alyssum in a vege garden?
Its flowers feed hoverflies, bees and other beneficial insects. Hoverfly larvae eat aphids, so a few patches of alyssum help protect nearby crops.
How do I keep alyssum flowering?
Shear it back lightly when flowering slows and water it in dry spells. It soon flowers again.
Can I grow alyssum in pots?
Yes. It suits pots, window boxes and hanging baskets at least 15 to 20 cm wide. Keep it moist and feed every week or two.
How deep should I sow alyssum seed?
Barely cover it. The seed is tiny and germinates faster and more evenly when only just covered, usually in 7 to 14 days.
Sources we checked: Yates NZ: How to grow alyssum; Yates NZ: Common problems of alyssum; Kings Seeds: Alyssum Carpet of Snow; Kings Seeds: White Alyssum for Orchards.