I purchased five Torenia annuals in 4″ pots from a greenhouse. They were all planted with fresh container soil in clean hanging baskets. Of the five only one has bloomed. I have fertilized with Miracle Grow 15-30-15 bloom booster monthly. The attached photo shows two plants in one basket, only one bloomed and even it has not been prolific. This basket is under the eaves facing north west and gets late afternoon sun. Last year my Torenia plant under a cedar tree was unbelievably beautiful with never ending bloms with it almost reaching the ground from a six foot hanger. I am wondering what if anything I am doing wrong this year.
Thank you for coonatcting the Toronto Master Gardeners with your question concerning your Torenia pots.
From your description my first inclination as to why your plants are not flowering profusely this year would be location.
Torenia flowers are adaptable to many locations; however, the ideal spot for these annuals would be where they receive morning sun and afternoon shade. This has never been more important than it has this summer where the days have been extremely warm and sunny. Ideally these plants prefer to grow in rich, moist, well-drained, slightly acidic soil with a pH between 6.0 and 6.5. Although Torenia prefers moist soil,they do not like wet feet since this plant is susceptible to root rot.
To keep your Torenia flowers prolific and blooming, provide a balanced, all-purpose plant food every two to three weeks. Aim for a 10-10-10, 20-20-20 or 5-10-5 balance. If you are using a liquid fertilizer, fertilize your plants twice a month throughout the growing season with a ratio of a tablespoon of fertilizer concentrate to a gallon of water.
This link provides more information on the care and growing requirements of this lovely annual.