Gadenin日本語Get the appRot is the main killer, at both ends of the season
Freesia corms rot in two predictable windows. The first is between planting and emergence, when the corm is damp but has no leaves to draw water off; the second is at the end of the season, when the leaves have died but the pot is still being watered. In both cases the corm goes soft, often with a sour smell, and by the time anything is visible above ground it is gone.
The prevention is the same at both ends: a gritty free-draining mix, a pot that actually drains, and restraint with the watering can. In open ground, avoid heavy soil that stays wet, and avoid low spots. Nothing you can spray fixes a corm sitting in cold wet compost.
Rot on growing plants shows differently. A stem that collapses at soil level, or a leaf fan that pulls away with a soft brown base, means the crown has gone, usually because water sat in the crowded center of the clump. Water at the compost surface rather than over the top of the foliage and this becomes rare.
Aphids hide in the leaf bases and spread virus
Aphids are the pest that matters on freesia. They gather in the tight overlapping bases of the leaf fan and on the developing flower spike, where they are easy to miss until the buds come out distorted or streaked. Because the leaves sheath each other closely, a spray applied casually over the top of the plant never reaches them.
Check by parting the leaf fan and looking down into it once a week from the point where the plant is a few inches high, and again as the spike starts to lengthen. Small numbers come off with a firm jet of water directed into the fan, or by wiping with a damp cloth. The reason to bother early is virus: aphids move viruses between corms, and virus is the usual explanation for a plant with pale streaks or mottling in the leaves and small malformed flowers. There is no cure. Dig out and dispose of an obviously virused plant along with its corm rather than replanting it.
Thrips also occur and produce silvery streaking on petals with tiny dark specks. They are far more common under warm dry conditions, which is another reason the cool regime is worth keeping.
| What you see | Likely cause | What to do |
|---|---|---|
| Nothing emerges, corm soft when dug | Rot from wet compost before rooting | Improve drainage, water only when the pot is light |
| Plenty of leaves, no flower spike | Warm nights during bud formation | Nothing this year; grow cooler next season |
| Long pale leaves leaning hard one way | Too little light | Move to full sun; expect weak stems this year |
| Stems bent over on the soil | No support, or top-heavy spikes | Normal habit; put supports in early next time |
| Pale streaks or mottling, small twisted flowers | Virus, spread by aphids | Remove plant and corm; control aphids on the rest |
| Silvery streaked petals with dark specks | Thrips | Grow cooler and more humid; remove worst flowers |
| Buds dry up without opening | Drying out during spike development | Keep evenly moist from bud to last flower |
| Leaf fan pulls away with a brown soft base | Crown rot from water in the center | Water at the surface; discard the affected plant |
The problems that are not really problems
Two freesia complaints come up constantly and neither is a disease. The first is the flopping. Thin grassy leaves and slender one-sided flower spikes always lean, and the better the plant is fed the more they lean. This is the plant's habit, not a deficiency, and the answer is support put in early rather than a search for a cause.
The second is the sharp bend near the top of the flower stem. It looks like damage, as though something snapped the stem, but every freesia does it and it is how the flowers are held facing upward. Leave it alone.
A third that is worth naming: corms that come up unevenly, some weeks behind others. This is usually a storage problem rather than a pest, and it points to corms rested somewhere too cool or too damp. It is a note to change the storage, not to treat the plants.
Losses in storage, and what to record about them
More freesia is lost in the storage months than to anything in the garden. Corms stored damp go moldy, corms stored cool break dormancy poorly, and a single soft corm in a sealed bag can spoil the batch. Store in paper or open trays, somewhere genuinely dry and warm, and look through them once partway through.
Keep a short record of losses with the cause where you can identify it: how many corms went in, how many emerged, how many flowered, and how many came out of storage sound. Those four numbers over two or three seasons will tell you plainly whether your problem is the planting, the growing conditions or the storage, and each of those has a different fix. Guessing between them is what makes the same loss repeat year after year.