The ornamental shrub known as ‘Hot Lips’ (Salvia microphylla) is a popular, prolific plant prized for its distinctive bi-colored flowers that attract pollinators. Regular pruning is necessary to prevent this plant from becoming overly woody or leggy, which ultimately reduces the number of blooms. Proper cutting back maintains a compact, appealing shape and ensures continuous flowering throughout the growing season.
Understanding the Pruning Schedule
The primary, most substantial cutback of the ‘Hot Lips’ plant should take place in late winter or early spring before the appearance of significant new growth. This timing is important because it allows the plant to recover and direct its energy into producing fresh stems once the growing season begins. Gardeners should wait until the danger of the last hard frost has definitively passed in their region.
Pruning too early, particularly in the autumn, can stimulate new, tender growth highly vulnerable to frost damage. The existing stems and foliage offer insulation and protection to the plant’s crown during cold weather. Therefore, leaving the plant intact during the winter provides a natural defense against freezing temperatures.
While the main structural pruning occurs annually in spring, light tidying can be performed during the active growing season. Removing spent flower spikes, a process known as deadheading, encourages subsequent flushes of blooms. This maintenance trimming can be done periodically from late spring through early autumn to keep the shrub neat and maximize flowering.
Techniques for Shaping and Rejuvenation
The specific amount to cut back depends on the age and condition of the plant, falling into two main categories: routine maintenance and hard rejuvenation.
Routine Maintenance
For maintenance pruning during the summer, the goal is to keep the shrub tidy and to encourage branching. Simply trim back the outermost stems and spent flowers by approximately one-third (1/3) of their length. This light reduction helps maintain a dense, bushy shape without drastically interrupting the bloom cycle. A new wave of flowers often results within a few weeks.
Annual Structural Cut
The more severe annual cut, performed in early spring, addresses the woody structure and resets the plant for the season. For a plant that is relatively well-shaped, cutting back by about one-half (1/2) to two-thirds (2/3) of the total height is generally appropriate. Make this cut just above a healthy leaf node or small, emerging shoot, as this is where the new growth will be concentrated.
Hard Rejuvenation
If the ‘Hot Lips’ has become old, woody, or severely overgrown and leggy, a hard rejuvenation cut is necessary. The plant can be cut back much more severely, sometimes leaving only 6 to 12 inches of old wood above the base. Focus on cutting back to where new green growth is visible at the crown, sometimes as low as 2 to 4 inches. Avoid cutting into old, bark-covered wood that shows no signs of active nodes, as this may not resprout.
Post-Pruning Care and Expectation
Immediately following the hard annual cut, the plant requires deep watering to stimulate root activity and support the rapid development of new shoots. Providing sufficient moisture is important after a severe reduction, as the root system must support the reduced top growth. Applying a balanced, slow-release fertilizer or rich compost around the base is beneficial at this stage.
This feeding provides the necessary nutrients to fuel the plant’s effort in producing new stems and foliage. Nitrogen supports lush, green growth, while phosphorus aids in strong root establishment. New, soft green shoots will begin to emerge from the lower nodes and the crown after the spring pruning.
The new stems will quickly mature, and the plant typically resumes its full flowering display within four to six weeks of the spring cut. Consistent moisture and warmth accelerate this process, leading to a compact, vigorous plant ready to sustain continuous blooming throughout the warmer months.