Gadenin日本語Get the appHow the year is shaped
Everything about the nemophila calendar follows from one fact: the plant dies when it gets hot. Work backwards from that. The flowering has to happen in the cool part of the year, the plant has to reach flowering size before then, and the seed has to be in the ground early enough to allow it. In a mild winter climate that means an autumn sowing and a long spring display; in a cold winter climate it means the earliest spring sowing the ground will accept.
The second fact that shapes the year is that the plant cannot be moved. There is no potting up stage, no hardening off and no planting out, so the calendar has fewer steps than most annuals and every one of them happens in the same square of ground. What replaces those steps is thinning, and it is the job most often skipped and most often regretted.
| Season | Main job | What to watch for |
|---|---|---|
| Late summer to autumn | Sow direct where winters are mild | Slugs on emerging seedlings, keep the soil damp |
| Winter, mild climates | Leave the rosettes alone | Waterlogging and crown rot on heavy ground |
| Late winter to early spring | Sow direct where winters are cold; thin autumn sowings | Frost is fine, standing water is not |
| Spring | Thin, weed, water evenly | Aphids on shoot tips, seedlings drawn up if too thick |
| Late spring | Peak flowering, no feeding | Flopping in wind and rain, mildew in dense patches |
| Early summer | Shear for a second flush or let it seed | Yellowing and collapse as heat arrives |
| Summer | Collect seed, clear the patch | Capsules shedding before you get to them |
Autumn and winter
Where winter lows stay above about 20F (minus 7C), sow once the summer heat has genuinely broken and the soil has cooled. The seedlings emerge within a fortnight and then more or less stop, sitting as flat green rosettes for months. That standstill is normal and useful, because the root is growing while the top is not. The only real winter jobs are keeping slugs off the young plants and making sure water is not standing around the crowns.
Do not feed, do not cover, and do not water an established autumn sowing unless the winter is exceptionally dry. Nemophila is hardy enough to shrug off frost at this stage and far more likely to be killed by a wet, airless row cover than by cold. Where winters are colder than the plant can take, there is nothing to do at all until late winter, when the seed goes in.
Spring, the working season
As soon as the ground can be raked, sow in cold winter climates and thin the overwintered rosettes in mild ones. Thinning is the whole job in early spring: take the patch to one plant every six to nine inches (15 to 23 cm) in two passes, pinching the surplus off at ground level rather than pulling them out. A patch left unthinned stretches, flowers thinly, and mildews in early summer.
Through spring, water evenly, weed by hand while you can still see the soil, and feed nothing. Check the shoot tips weekly for aphids as the weather warms and deal with them by hosing while the colonies are small. Flowering usually starts in mid to late spring and covers the patch within a fortnight, at which point the only remaining decision is whether to shear for a second flush when the first one thins.
- First thinning at two true leaves Take the patch to one plant every three inches (8 cm). Doing this early is far easier than untangling crowded plants later.
- Second thinning at four true leaves Final spacing of six to nine inches (15 to 23 cm). Pinch out at the ground so the roots of the keepers stay undisturbed.
- Weekly tip check from mid spring Turn over a few shoot tips and look for aphids and distortion. Two minutes a week saves a heavy infestation at peak flowering.
- Water at the base, mornings only Keep the crowns dry going into the night. Once flowering starts a dense patch holds moisture for a long time.
- Mark the best plants at peak flower Label the two or three plants that stood up best and flowered longest, so you know which to take seed from later.
Early summer and the end of it
When the first flush starts to thin and you can see stems through the flowers, decide quickly. If the weather is still cool, shear the top third off the whole patch and water once; a second flush follows in two or three weeks. If warm weather has already arrived, leave it, because the plant will not rebuild in heat and the growth that is there is now ripening seed.
As day temperatures settle above about 80F (27C) the plants yellow from the base and finish within a week or two. Stop watering at that point. Leave the stems standing until the capsules go papery brown, collect seed from the marked plants, shake the rest over the ground if you want it to come back, and then pull everything out and put a heat tolerant summer plant in the space. The ground is free far earlier than most annual beds, which is worth planning for.
The end of a nemophila patch looks like a disaster and is not. Yellowing and collapse in the first hot week is the normal end of an annual that has completed its life, and it happens whether you water it or not.
The dates worth carrying into next year
Four dates make the whole schedule reusable: the day you sowed, the day the seedlings emerged, the day the first flower opened, and the day the patch collapsed in heat. With those, you can count backwards next season from the weather you actually get rather than from a general recommendation, and you will know within a week whether your usual sowing date is early enough.
Add the position of the patch and how much midday sun it received, and note the date the capsules browned so you do not miss the seed. Two seasons of those six notes is enough to run nemophila on autopilot in your own garden, and it is a plant where being a fortnight early with the sowing is worth more than everything else on this page put together.