Ipomoea tricolor 'Heavenly Blue'

How to grow annual climbers from seed

Find out how to grow annual climbers, such as black-eyed Susan and morning glory, from seed.

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
To do
To do

Do not To do in January

Do not To do in February

Do To do in March

Do To do in April

Do To do in May

Do not To do in June

Do not To do in July

Do not To do in August

Do not To do in September

Do not To do in October

Do not To do in November

Do not To do in December

Easy to grow, climbing annuals will flower non-stop from June until the frosts, producing striking blooms and sculptural leaves. Because they grow 1.8m to 3m or more in a season, half the joy in growing them is producing a showstopping plant from one small, inexpensive seed.

Sweet peas aside, annual climbers are rarely seen in borders, but they’re easy to grow from seed with a heated propagator in a greenhouse, or a frost-free porch or indoor window sill. Species to try include Spanish flag (Ipomoea lobata), Canary creeper (Tropaeolum peregrinum), black-eyed Susan (Thunbergia alata) and morning glory (Ipomoea).

Annual climbers are often grown as fast cover-ups for sunny fences and trellises, but they make excellent pot plants for large containers on a sunny patio – be sure to provide them with some support in the form of a wigwam or obelisk.

Here’s how to grow annual climbers from seed.

Easy to grow, climbing annuals will flower non-stop from June until the frosts, producing striking bloom.

You will need

  • Annual climber seed
  • Glass bowls for soaking seed
  • Seed labels
  • 10cm pots
  • Larger pots for potting on
  • Seed-sowing compost
  • Heated propagator
  • Twigs for support
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Step 1

To encourage germination, soak the seeds overnight in cold water to soften their coating. Keep the different varieties separate and clearly labelled.

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Step 2

Use 10cm pots and fill with a seed-sowing compost. Scatter the seeds on the surface, then cover with another thin layer of compost.

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Step 3

Keep pots covered in a propagator at approximately 21-24°C (average room temperature). Water regularly to prevent the compost drying out but don’t let the pots become waterlogged.

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Step 4

Seedlings should appear within two to three weeks. Once the first true leaves appear, transfer each seedling to its own pot, holding it by the leaf not the stem. Keep watered and in a frost-free place.

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Step 5

Once climbers start to grow, give the pots some more room and push twiggy supports into the compost to prevent plants tangling with each other. From April, gradually harden off plants in readiness for moving outdoors.

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If you don’t want to sow seeds in February, you could wait until the weather warms up in April and sow pots in a coldframe for slightly later-flowering plants.

Cold frame