Don visited Ann Goldstone, who has a problem with her wisteria. The wisteria was planted 8 years ago, but has never flowered. It shares a garden bed with standard roses (Rosa ‘Iceberg’), which are watered well and fertilised every 6-8 weeks.
Don’t fertilise
Don advised against planting wisterias in the same area as roses or any other ‘gross feeders’. If an established wisteria is given too much fertiliser and water, it will put all of its energy into growth rather than the production of flower buds. Don felt that Ann’s wisteria would probably never flower well as long as it was in the rose bed. He suggested cutting down on the rose food or perhaps trying one of the special flower promoting fertilisers, such as Manutec Bloom Booster. These fertilisers are low in nitrogen and high in potassium and phosphorus.
Wisteria growing tips
Plant in full sun
After planting, water well. Apply fertiliser in spring and midsummer.
Once the plant is established, stop watering and fertilising.
Prune after flowering.
Avoid pruning late in the growing season or in winter, or you may remove flowering wood.
Further information
Manutec Bloom Booster costs around $7 from nurseries and K-mart.