Japanese morning glory care guide

Ipomoea nil

Also known as: Morning glory, Ipomoea nil

Pets and children

Considered toxic

Compounds in the seeds have been linked to vomiting, diarrhea, unsteadiness and agitation in dogs and cats; store seed especially well out of reach and consult a veterinarian (or a doctor, for a child) if eaten.

How often to water Japanese morning glory

Spring–Summer (Mar–Sep)
Every day
Water seedlings once the topsoil dries and, as the vines grow in summer, about daily, morning and evening in the hottest weather, as a guide.
Autumn (Oct–Nov)
Every 2 days
A plant still flowering in fall wants thorough water when dry, usually about every one to two days as it cools.
Winter (Dec–Feb)
Every 7 days
An annual that dies around the first frost: no watering is needed in winter, and generally you just store the dried seed for spring.

Light and placement for Japanese morning glory

Full sun outdoors all day is the guide; in low light the vines grow but flower less, and light from streetlamps or windows at night can stop bud formation.

Overwintering Japanese morning glory

Overwintering guide: 5°C (41°F) or above

An annual that is not overwintered: generally collect seed in fall and sow again around May, keeping the seed in an envelope somewhere cool and dry.

Fertilizing and repotting Japanese morning glory

Fertilizer

Mix slow-release fertilizer in at planting and give liquid feed about every one to two weeks from the true-leaf stage to September; too much nitrogen gives vines instead of flowers.

When to repot

Spring–Summer (Mar–Sep)

Common problems with Japanese morning glory

  • Sown in cold April it fails to germinate and seedlings stall.
  • Drying out in midsummer wilts the plant and drops the buds.
  • Lit at night, the vines grow but it does not bloom.

Tips for growing Japanese morning glory

  • Soaking seed overnight or nicking the coat gives even germination.
  • Pinching the tip at five to eight true leaves multiplies side shoots and flowers.
  • Set up a ring support before the vines run and wind them on as they grow.

These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.

Keep your plant log going

Greenery is a free app that keeps your plant care going, with watering reminders and photo records. Available on iOS and Android.

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