Cutting back Petunias encourages new growth and more branching, and in return, more blooms! On long stems that look “leggy,” pinch the stem back 1 to 2 in. (2.5 to 8 cm), making sure to cut back past the desired branch length (new growth will fill in that space). These growth tips will be tender and can be pinched using your forefinger and thumb, or a scissors if necessary.
Once the branch is pinched back, new growth will begin to develop, creating the spreading form that Wave Petunias are known for. Wave Petunias will continue to hold their prized growth habit if they receive full sun (at least 5 to 6 hours per day), along with regular watering and fertilizer (once a week with liquid feed, or plant with slow-release fertilizer).