The genus Penstemon includes many species of flowering wildflowers, which are native to North America. The Venus penstemon (Penstemon venustus) is found in Washington, Oregon, northeastern California, Idaho and Utah. It is a perennial shrub that sports lavender flowers and grows to 2 feet tall. This penstemon is useful for controlling erosion and beautifying dry, scrubby areas with its profusion of summer-long blooms. You can introduce this attractive wildflower to your garden if you live in an area that has dry summers and winters that can drop as low as minus 30 degrees Fahrenheit. To keep your Venus penstemon tidy and healthy, prune it every year in the spring and fall.
Pruning the Venus Penstemon
Look for new growth at the plant's base and along its stems in April or May.
Remove old flower stalks at their base by cutting them off with your clippers as close to the main plant stalk as possible, without cutting into the stalk.
Cut out all old stems from the bottom of the plant with your clippers, making certain that you do not damage the plant's main stalk.
Cut Venus penstemon back by about one-third in the fall. Using your clippers, snip off every branch one-third of the way back to the plant's main stalk. It's important to leave some foliage to protect the plant from frost.
Pull out all weeds and other plants that might compete with the penstemon after you prune it in the fall. Be careful not to disturb the roots of your penstemon when you pull out neighboring weeds. Also, shake the soil off the roots of the weeds you remove to give your penstemon extra soil that it might need to help protect it from cold temperatures.