Gadenin日本語Get the appRich soil gives vine and no flowers
This is the fact that decides whether your morning glory season is a success. On fertile ground, or with a general purpose fertilizer applied through the summer, the plant grows superbly: thick stems, large dark leaves, ten feet of vine by midsummer, and almost no flowers. Gardeners who see that growth usually conclude the plant needs more feeding, apply more, and get more leaves. It is a difficult loop to break unless you know what is happening.
Nitrogen drives leaf and stem growth at the expense of flower buds. Morning glory is unusually sensitive to it. Grown on ordinary or even poor soil, the same plant makes a moderate amount of vine and covers itself in flowers, which is what you actually want. Lean ground is not a compromise here; it is the correct growing condition.
So do not dig manure or compost into the bed, do not feed with a balanced or high nitrogen fertilizer, and do not plant morning glory where a heavy mulch has just gone down. If you feed anything at all, use a high potassium liquid feed such as a tomato feed, at half strength, every two or three weeks from the first flower bud onward. Potassium supports flowering without pushing leaf growth.
| Situation | What you see | What to do |
|---|---|---|
| Ordinary unimproved soil, no feed | Moderate vine, heavy flowering | Nothing; this is the target |
| Rich soil or general fertilizer | Huge leafy vine, few or no flowers | Stop feeding entirely; flowering usually resumes in three to four weeks |
| Container, no feed at all season | Pale small leaves, short vine, few flowers | Half strength high potassium feed every two weeks |
| High nitrogen lawn feed drift | Dark floppy growth, no buds | Stop, water heavily to leach, wait it out |
| Poor dry soil, no water | Yellow lower leaves, buds dropping | Water more; fertility is not the problem |
Water steadily, and expect containers to need it daily
Morning glory carries a lot of leaf on a thin stem and loses water quickly. In the ground, a deep soak twice a week in hot weather is better than a light sprinkle every day, because it draws the taproot down and the plant then rides out a hot spell without wilting. Water the soil at the base rather than over the foliage.
In a container the picture is different. A full grown vine in a twelve inch (30 cm) pot will empty it in a single hot day and wilt hard by mid afternoon. Water every morning in summer, and twice on the hottest days if the pot is against a sunny wall. Choose the largest container you can and stand it where it gets some shade on the pot itself even if the vine is in full sun.
A morning glory wilting at midday and recovering by evening is normal on a hot day and needs no action. One still wilted at breakfast the next morning is genuinely dry and has probably already dropped its next few buds. Buds abort within a day or two of a serious drying, so consistency matters more than volume.
- Check by weight, not by the surface Tip a container slightly or lift its edge. A dry pot is startlingly light. The surface of a compost dries out within hours of watering and tells you nothing about the root zone six inches down.
- Mulch the base in the ground An inch (2.5 cm) of gravel, bark or spent compost over the root zone holds moisture through hot weather. Keep it an inch clear of the stem so the base does not stay wet and rot.
- Water early rather than in the evening Morning watering fills the plant before the heat of the day, which is when the flowers are open and losing the most water. Evening watering leaves foliage damp overnight and encourages mildew on crowded vines.
Sun, heat and the position that suits it
Give morning glory the sunniest position you have. Six hours of direct sun is a working minimum and eight or more is better. In partial shade the vine grows perfectly well, climbs just as high, and flowers thinly, with the few flowers it does produce appearing near the top where the light is. If a well fed vine and a shaded vine both fail to flower, they look identical from the ground; the difference is what you can do about it.
The plant loves heat and is not troubled by temperatures in the nineties Fahrenheit (mid thirties Celsius) as long as it has water. It has no frost tolerance at all. A light frost blackens the whole vine overnight and ends the season, which is worth planning for rather than being surprised by.
Wind is the other consideration. A vine on netting is a solid sail once it fills out, and a summer storm can tear the whole screen off a wall or snap stems where they cross the support. Fix supports far more firmly than the young plants seem to warrant.
Pests, mildew and what to record
Aphids cluster on the growing tips and the flower buds, and heavy infestations distort the new leaves. A jet of water knocks them off and repeated visits usually bring predators in. Spider mite shows as fine pale stippling on leaves against a hot dry wall, and is far more likely on a plant that has been allowed to run dry repeatedly. Powdery mildew appears as gray patches on crowded lower leaves late in the season; improve airflow by thinning the tangle rather than spraying.
Leaf miners leave pale winding trails inside the leaf. They look alarming and matter very little on a vine carrying hundreds of leaves. Pick off the worst leaves and ignore the rest.
Keep a note of your feeding, or the absence of it, alongside your flowering dates. The connection between a spring feed and a flowerless midsummer is separated by weeks, and almost nobody joins the two without a written record. One season of notes usually settles the question of how lean your ground needs to be for good flowering.
If a vine is all leaf and no flower, resist the urge to feed it. Stopping every feed and letting the ground go lean is the fix, and it usually takes three to four weeks before buds start appearing.