Gadenin日本語Get the appCrown rot in wet soil is the one that kills
Almost every dead salad burnet plant died of wet feet, not of cold. This is a plant of dry chalk grassland with a taproot built for drainage, and it will take minus 20F (minus 29C) without flinching while dying quietly in a soggy winter bed at 40F (4C).
The symptoms are obvious once you look. The center of the rosette goes soft and brown, leaves pull away from the crown with almost no resistance, and the base of the plant smells sour. By that stage the plant is finished. There is no treatment worth attempting; lift it, bin it, and fix the site.
Prevention is entirely about the site and the autumn tidy-up. Plant on free-draining ground, raise the bed or work grit into heavy clay, and set the crown level with the surface rather than in a dip that collects water. Then, in late autumn, clear fallen leaves off the crowns and strip away dead outer growth. A wet mat of leaf litter sitting on an evergreen crown all winter is the single commonest cause of the problem. Do not mulch over the crown for winter protection; the plant does not need it and the mulch does the damage.
| Symptom | Likely cause | What to do |
|---|---|---|
| Soft brown center, sour smell at the base | Crown rot from waterlogging | Remove the plant, improve drainage, replant on a mound |
| White dusty coating on the leaves | Powdery mildew | Cut the plant back hard, clear the debris, thin the clump |
| Ragged holes mid-leaf, slime trails | Slugs and snails | Clear debris from the crown, hand-pick after dark, ring with grit |
| Leaves tough and bitter in early summer | Plant has run to flower | Cut all flower stems at the crown, then cut the plant back hard |
| Sprawling floppy soft growth | Soil too rich or over-fed | Stop feeding, cut back, and lift to a poorer position in spring |
| Clusters of small insects on the flower stem | Aphids | Cut the flower stem out at the crown, which removes them with it |
Powdery mildew in a congested plant
Mildew shows as a white dusty coating, usually starting on the older outer leaves and on any part of the plant lying flat against damp soil. It appears in warm still weather with poor air movement, and it is far more common in a crowded, over-fed, three-year-old clump than in a well-spaced young one.
It rarely kills the plant but it spoils the crop, and because salad burnet is eaten raw a mildewed leaf is simply not usable. The response is physical rather than chemical: strip off every affected leaf and bin it rather than composting it, thin out the center of the clump so air moves through, and water at the base in the morning rather than over the leaves in the evening.
If it has taken hold across the whole plant, cut everything down to an inch (2.5 cm) above the crown, clear all the material away and water. The regrowth comes clean. This same hard reset fixes mildew, leaf miner blotches and coarse foliage in one operation, which is why it is worth doing routinely in midsummer whether or not there is a problem.
Slugs, aphids and the pests that barely register
Salad burnet's mature foliage is too tough and too astringent to interest most pests, and an established plant is left almost entirely alone. The exceptions are narrow and predictable.
Slugs and snails go for the soft new growth in early spring and for seedlings at any time. A row of newly emerged seedlings can vanish in a night. Clear old leaves and debris from around the crowns at the end of winter to remove the daytime shelter, ring seedlings and young plants with grit or wool pellets, and hand-pick after dark for the first two weeks of new growth. Once the foliage has firmed up the problem stops.
Aphids appear on flower stems rather than on leaves, clustering on the soft upright growth. Since you should be cutting those stems out anyway, the treatment and the routine job are the same thing: cut at the crown and the colony leaves with the stem. A plant kept properly deflowered almost never has aphids.
Do not spray anything on a plant whose leaves you eat raw and often pick without washing. Everything salad burnet suffers from is better handled by cutting, clearing and spacing.
- Clear the crowns in late autumn and late winter Rake fallen leaves off, strip dead outer growth, and open up the center of each rosette. This removes slug shelter and stops wet sitting on the crown.
- Check new spring growth after dark For the first fortnight of soft growth, look over the plants by torchlight and pick off slugs. It is the only time of year they matter.
- Cut flower stems on sight Weekly from late spring. This removes aphid colonies, prevents self-seeding and keeps the leaves from going bitter, all in one cut.
- Reset a troubled plant Cut everything to an inch (2.5 cm) above the crown, remove and bin the material, water. A clean flush follows in two to three weeks.
Problems that are not pests at all
The complaint you will hear most often about salad burnet is that it tastes bitter and tough. Nine times out of ten this is not a fault in the plant but a fault in the picking: the big outer leaves are old and always harsh, and only the young central leaves carry the cucumber flavor. The tenth time it is a plant that has been allowed to flower, or one that has dried out at the root, and both are fixed by cutting rather than by any treatment.
The second false alarm is soft floppy sprawling growth with no flavor. That is over-feeding, not disease. Salad burnet wants poor, free-draining, neutral to alkaline ground and it punishes generosity. Stop feeding, cut the plant back, and move it somewhere thinner next spring.
The third is a clump that has gone woody in the middle with leaves only around the rim. That is simply age. It is not going to recover on its own and no amount of care will fix it, but division in early spring turns one tired plant into four good ones.
Note the first date you see slug damage and the first date a flower stem appears, every year. Both repeat closely from season to season, and knowing them lets you clear the crowns and start the weekly patrol a week early rather than a fortnight late.