How to Grow Salad Burnet in Australia

Salad burnet (Sanguisorba minor) is a hardy, clump-forming perennial of the rose family, Rosaceae, grown for young leaves with a mild, nutty cucumber flavour. It stays green through mild winters, so it can give salad leaves right through the cool months. The usual mistake is letting it flower, when cutting the flower stems keeps young leaves coming.

Three mistakes that matter

1. Letting it run to flower. Flower stems can reach 75 cm, the leaves are best before flowering, and the plant self-sows readily. It is a minor environmental weed in South Australia and Victoria, so cut the stems as Cutting Back describes.
2. Burying the seed. Salad burnet seed needs light to germinate, so seed sown at a normal depth may never come up. Cover it only lightly, at the depth Sowing direct gives, and keep the surface damp until seedlings appear.
3. Moving an older plant. Older plants grow a strong taproot and do not transplant well. Sow where the plant is to grow, or plant out seedlings while they are small, and divide a big clump rather than shifting it.

When to plant

Seed germinates best with the soil between 10 and 21°C, so most zones sow in autumn and spring and skip the hottest months. Salad burnet is long-lived, so one sowing gives plants that crop for several years.

At the hot end of a window, sow into cells kept in light shade and plant out once the weather cools. In temperate and Mediterranean gardens, a sowing around Anzac Day grows through winter, when the leaves are usually mildest.

Site, soil and setup

In the wild, salad burnet grows on chalk grassland, so it wants sun, free drainage and soil that is neutral to slightly limy.

Because it stays put for years, salad burnet sits outside the vegetable rotation. See soil pH explained before liming.

Container growing

Salad burnet grows well in a pot, where its rounded clump suits a sunny balcony or courtyard. Choose a pot at least 30 cm across and 30 cm deep for the taproot. A standard 40 cm pot, about 28 L, is big enough. Fill it with a premium potting mix. The store sells one burnet, and it suits pots, since a plant spreads only about 30 to 40 cm.

• Water: when the top few centimetres of mix feel dry, until water runs from the drainage holes, and more often in hot weather.
• Feed: fish and seaweed blend at half strength, about 12.5 mL per 9 L, fortnightly in spring and summer.
• Position: full sun in cool districts, morning sun and afternoon shade where summers are hot.

Sowing Seeds

Sow straight into the bed, or into cells for planting out while young (see Three mistakes that matter). The store's Burnet seeds are salad burnet, Sanguisorba minor.

Sowing direct

• Sow seeds about 2.5 cm apart and cover them lightly, 3 to 5 mm deep (see how deep to sow).
• Keep the surface moist; seedlings appear in 7 to 21 days at the soil temperature When to plant gives.
• Thin the seedlings in stages to 30 cm apart once they can be handled.
• Space rows about 45 cm apart.

Starting in cells

• Start 6 to 8 weeks before planting out, with 3 to 4 seeds per cell of moist seed-raising mix, barely covered.
• Thin to the strongest seedling in each cell.
• Harden off the young plants (set them outdoors a little longer each day so they adjust to sun and wind) for about a week.
• Plant them out at 5 to 10 cm tall, 30 cm apart.
• Water them in with seaweed solution at half strength, 15 mL per 9 L.

Care by growth stage

Even moisture decides the crop. Established plants survive dry spells, but the leaves stay tender only with plenty of water in hot weather. Feed at half strength at most, because salad burnet grows naturally on poor, limy soils.

Salad burnet is very cold hardy, and established plants carry on through frost. If growth stalls in poor soil, a light scatter of all-purpose controlled release granular (NPK around 14-5-10) can help.

Cutting Back

Cutting keeps the clump making young leaves and, as Three mistakes that matter explains, stops it seeding into the wider garden.

• Cut each flower stem at its base as it rises, before the round green flower heads ripen.
• Cut the whole plant back after flowering, or whenever the leaves turn tough from infrequent picking, to encourage tender new growth.
• Pull stray seedlings while they are small, before the taproot deepens.
• Divide a crowded clump in spring (see dividing perennials), replanting more pieces than you need, since only some take.

Companion planting

Salad burnet sits best among other perennial herbs, but it wants more summer water than thyme or oregano, so water it at its base.

Grows well with

• Thyme, which wants the same sunny, well-drained spot and stays in place for years.
• Oregano, another sun-loving perennial for a permanent herb bed.
• Chives, a perennial salad herb picked on the same trips to the garden.

Keep apart

• Mint, whose runners crowd a low clump and which prefers damp ground.
• Annual beds dug over every season, where digging damages the burnet's taproot.

Harvesting Leaves

Start picking once plants are about 20 to 25 cm tall, usually 8 to 13 weeks after sowing, taking the young leaves first.

• Pick in the morning, when the leaves are fresh.
• Snip whole young leaf stems with scissors.
• Keep picking regularly, or cut the plant back as Cutting Back describes.

Use the leaves fresh, because they turn bitter when dried. Wrapped in a damp paper towel inside a perforated bag in the crisper, picked leaves keep for 2 to 3 days.

Chop young leaves into salads, sandwiches, soups and dips, or add whole sprigs to iced drinks.

Common problems

Seed slow to come up. Salad burnet germinates slowly, and seed buried too deep or sown into soil outside the range When to plant gives may not appear. Read more

Bitter leaves in summer. Hot, dry weather can turn the leaves bitter, so water deeply, mulch and give afternoon shade in hot districts.

Plants rot or fade over winter. Salad burnet does not tolerate poor drainage, so a wet crown in heavy soil can kill it; move new plants to a raised bed. Read more

Brown spots on the leaves. Leaf spot can appear in wet weather, so pick off spotted leaves, water at the base and keep the spacing Sowing direct gives.

Pests and diseases

Salad burnet is rated generally free of pests and diseases, so trouble mostly falls on seedlings.

Slugs and snails, including grey field slug (Deroceras reticulatum). They feed after dark and in wet weather, and can chew seedlings to the ground. Search with a torch about two hours after sunset, and set beer traps where they are active. Read more

Damping off (Pythium species and Rhizoctonia solani). Young seedlings rot at soil level and fall over, most often in wet mix. Sow into clean seed-raising mix, avoid overwatering and thin crowded seedlings. Read more

Prevention first

• Sow in fresh seed-raising mix, with clean trays and tools.
• Clear old plant trash from trays and beds between sowings.
• Keep mulch back from young seedlings, since snails shelter in it by day.
• Set out citrus rind halves and collect the snails sheltering under them before dark.

Tips

1. Strip older, wiry stems over the salad bowl: run your fingers down each stem and the leaflets fall off whole.
2. Freeze young leaves in ice cubes for cool summer drinks.
3. For burnet vinegar, cover a jar of leaves with white wine vinegar, keep it in the fridge, and strain after a few weeks. Follow CSIRO's preserving advice, because herbs bottled without enough acid can carry botulism.