Garden Q&A: Why didn't my perennial sweet pea bloom this year?

 Whether you're a gardening beginner or expert, Irish Examiner columnist Peter Dowdall has the answer to your questions    

Perennial sweet pea flowers. File pictures

Question

My perennial sweet pea did not flower this summer. Can you shed some light on the problem?

Answer

Perennial sweet peas often fail to flower if conditions aren’t quite right. 

Too much nitrogen in the soil encourages leafy growth instead of blooms, so avoid rich compost or general-purpose feeds and use a high-potash fertiliser such as tomato feed. 

They also need full sun, at least six hours a day, as shade from fences or nearby plants can prevent flowering.

The sweet pea plant, Lathyrus odoratus. 

Older clumps may become crowded and lose vigour, so divide them in early spring or autumn and replant the youngest, healthiest sections.

If the plant was cut back or moved earlier this year, it may still be settling in and will likely flower next season once its roots are established. 

With better light, feeding and division, it should bloom beautifully next summer.

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