Anise Problems: Aphids, Slugs, Damping Off and Heads That Never Dry

The biggest hazard is the calendar

Before any pest, the thing most likely to cost you an anise crop is time. The plant needs roughly four frost free months to carry seed to ripeness, and a cool cloudy summer stretches that further. A gardener who sows two weeks late, or whose spring stays cold, ends up in autumn with a stand of green heads and the first frost coming. No spray or feed fixes this, and it is worth naming as a hazard because it is so often misdiagnosed as a disease.

The remedies are all about the front of the season: sow as soon as the soil reaches 60F (15C) and not a week later, use the warmest sheltered bed you have, and keep the seedlings weed free so they never stall. If after all that the heads are still green as autumn comes, cut them and finish them under cover rather than losing everything to frost.

Slugs and damping off in the seedling stage

Anise seedlings are small, soft and unusually slow, so the vulnerable period runs for several weeks rather than a few days. Slugs and snails will clear a freshly emerged band overnight in damp weather, and because germination is slow anyway gardeners often assume the seed failed rather than that something ate it. If a row vanishes, go out after dark with a torch before you blame the packet.

Damping off is the other seedling problem, and it comes from sowing too thickly into cold wet soil with no air movement. The seedlings topple at ground level with a pinched, waterlogged stem. Since anise is deliberately sown thickly for support, the defense is warmth and drainage rather than wide spacing: wait for the soil to warm, sow into ground that drains, and do not water in the evening.

1. Check after dark when a band disappears Slime trails and missing seedlings with no stumps mean slugs. Trap or barrier the next sowing rather than mourning the last one.
2. Do not mulch a young band Mulch laid over emerging seedlings gives slugs cover and damp exactly where the softest growth is. Wait until the plants are thinned and standing.
3. Water in the morning, at the base A dense stand that goes into the night with wet foliage is the classic setup for damping off and later for leaf spot. Water early and at soil level.
4. Resow gaps immediately, not later A gap filled two weeks late gives plants that flower two weeks late and never ripen. If a section fails, resow it the same week or write it off.

Keep a short spare row of anise sown at the same time in a corner of the bed. Because you cannot transplant to fill gaps, having a second band already growing is the only practical insurance against a slug raid on the main stand.

Aphids in the umbels and foliage

Aphids are the main insect pest once the plants are growing, and the fine upper foliage and the umbels hide them well. The usual first sign is a sticky feel to the leaves or ants running up the hollow stems. A colony sitting in a flowering head reduces seed set directly, and on a crop with only one harvest a year that is worth catching early.

Check the undersides of leaves and into the developing heads twice a week from the time the flower stem rises. Soft overfed plants are hit hardest, which is one more reason to keep the crop lean. A firm jet of water from below dislodges most of a colony, and aphids knocked off rarely climb back up.

1. Wash colonies off with water Direct a firm spray up into the head and under the foliage every two or three days until you stop finding them. Avoid doing this once seed is drying.
2. Let the umbels do their own pest control Flat white anise umbels are excellent hoverfly, lacewing and parasitic wasp plants. Left to flower, an anise bed usually clears its own aphids and helps the crops around it.
3. Pull one badly infested plant rather than treating the stand Removing a single colonised plant early protects its neighbors and costs almost nothing in a dense stand where plants are four to six inches (10 to 15 cm) apart.
4. Stop any spraying once seed is filling You are going to eat the seed whole and unwashed after drying. From flowering onward, physical removal is the only sensible approach.

Wet weather, flopping and mold in the heads

The characteristic anise failure in a wet summer is mechanical. The stand goes over in a storm, the heads lie on the soil, and seed that was two weeks from ripe goes moldy and gray instead of drying. Once heads are on the ground they rarely recover, so this is a problem to prevent rather than to treat. Support the block early, keep it out of the wind, and improve drainage so the roots are not sitting in water when the storm comes.

The related problem is mold in cut heads. A head bagged while damp will be furred and useless within a week, and the smell will tell you before you look. Cut dry, hang in a place with real air movement, and check the bags after a few days. Anything gray or musty goes on the compost, because mold in a jar of dried seed spreads to the whole batch.

Note the date you first see aphids, the date of any storm that flattens the stand, and the date leaf spot appears. These dates repeat closely from year to year, so next season you can put support in or check a head a week before the trouble rather than a week after.