How far apart should I plant Honesty?

About 35 cm (14 in) apart, centre to centre. A mature plant spreads 30–45 cm (12–18 in).

Does Honesty need full sun?

Part sun to part shade: at least 4 hours of direct sun a day.

How much water does Honesty need?

Moderate water. Drought tolerance is moderate and waterlogging tolerance none.

How cold-hardy is Honesty?

It tolerates about -25 °C (-13 °F) once established, roughly USDA zone 5. As a biennial it is usually planted out after the last frost and flowers in its second year.

When does Honesty flower?

About 43–57 weeks after planting, for 4–7 weeks.

Is Honesty poisonous to cats and dogs?

For cats it is not well documented; for dogs not well documented; for people not known to be toxic. Young roots and seeds are eaten in small amounts; pet effects are not documented in ASPCA lists.

What grows well with Honesty?

Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas.

Honesty Lunaria annua

Honesty (Lunaria annua) is a biennial flowering plant in the Brassicaceae family, native to Southeast Europe (Balkans); naturalised across Europe. It grows 60–90 cm (24–35 in) tall and 30–45 cm (12–18 in) wide, wants part sun to part shade and moderate water, and is hardy to about -25 °C (-13 °F). Space plants about 35 cm (14 in) apart.

Plan Honesty in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.

Honesty at a glance

Type	Biennial flowering plant
Family	Brassicaceae
Mature height	60–90 cm (24–35 in)
Mature spread	30–45 cm (12–18 in)
Spacing	35 cm (14 in) centre to centre
Sun	Part sun to part shade, at least 4 h of direct sun a day
Water	Moderate; drought tolerance moderate, waterlogging tolerance none
Soil pH	6–7.5
Cold hardiness	About -25 °C (-13 °F) once established (roughly USDA zone 5)
Heat stress	Likely above about 30 °C (86 °F)
Flowering	about 43–57 weeks after planting, for 4–7 weeks
Wind tolerance	Low
Pollinator value	High
Edible	Yes: young leaves, roots, seeds
Native to	Southeast Europe (Balkans); naturalised across Europe
Common in gardens of	🇬🇧 United Kingdom, 🇫🇷 France

Is Honesty toxic?

People: not known to be toxic
Cats: not well documented
Dogs: not well documented

Young roots and seeds are eaten in small amounts; pet effects are not documented in ASPCA lists.

If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.

Companion planting: what to grow with Honesty

Good neighbours

good With Rhubarb: Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Evidence D
good With Nasturtium: Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas. Evidence C

Shared pests and diseases

Clubroot: Clubroot spores persist in soil up to 20 years; keep brassicas in a rotation. Evidence B

Questions about Honesty

How far apart should I plant Honesty?: About 35 cm (14 in) apart, centre to centre. A mature plant spreads 30–45 cm (12–18 in).
Does Honesty need full sun?: Part sun to part shade: at least 4 hours of direct sun a day.
How much water does Honesty need?: Moderate water. Drought tolerance is moderate and waterlogging tolerance none.
How cold-hardy is Honesty?: It tolerates about -25 °C (-13 °F) once established, roughly USDA zone 5. As a biennial it is usually planted out after the last frost and flowers in its second year.
When does Honesty flower?: About 43–57 weeks after planting, for 4–7 weeks.
Is Honesty poisonous to cats and dogs?: For cats it is not well documented; for dogs not well documented; for people not known to be toxic. Young roots and seeds are eaten in small amounts; pet effects are not documented in ASPCA lists.
What grows well with Honesty?: Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas.

Sources and evidence

Evidence grade C (C: plausible, mixed evidence).

RHS Plant Finder, Royal Horticultural Society
Plants For A Future database, PFAF

Notes and assumptions

Typical garden-form values; cultivars and local conditions differ.
Biennial that self-seeds; sow in early summer to flower the following spring. The silvery seed discs are used in dried arrangements.

Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.

Related plants

Broccoli Brassica oleracea var. italica
Cauliflower Brassica oleracea var. botrytis
Cabbage Brassica oleracea var. capitata
Kale Brassica oleracea var. sabellica
Radish Raphanus sativus
Bok choy Brassica rapa subsp. chinensis
Brussels sprout Brassica oleracea var. gemmifera
Kohlrabi Brassica oleracea var. gongylodes