Verbena plants are beautiful and ideal to add to any garden. While they require less attention when pruning than other herbs and evergreens, you still need to cut them from time to time to keep them tidy and stimulate growth. The most important pruning phase takes place in the first days of spring. In the summer, you can remove the top of the plant to encourage flowering. In autumn, you just need to remove the dead seeds and flowers. However, avoid pruning the verbena too much or you will limit its growth.
Steps
Part 1 of 3: Prune the Plant in Early Spring
Step 1. Wait for the new twigs to appear in spring
They will usually start growing after the last frost. You may notice new green stems along the base of the plant or leaves growing from the branches. This is a sign that you should prune the vervain.
Step 2. Prune old branches about 5cm above the ground
Older stems are usually long, woody, and hard. Use hedge shears to cut these branches in favor of the newer, greener ones, which will usually only come a few inches tall. This way, the new parts will grow better, preventing older branches from taking up the whole plant.
- Just leave 5 cm of stem. The plant will quickly grow back at this stage if you prune it close to the ground. If you notice new stems growing from old branches close to the ground, cut just above those spots.
- Be sure to wear protective clothing, such as gloves, when pruning plants in the garden.
Step 3. Remove dead branches close to the ground
Look for stems or branches that have turned brown or have fallen to the ground. Cut them at the base of the plant. Throw them in a compost bin or throw them away.
If you see mold or discolored areas on the leaves, cut them back, as they may be diseased
Step 4. Pull out the shoots
This way the plant will not propagate. Verbena spreads its seeds very easily and before you know it, it could infest your entire garden. Look for cross-shaped shoots around the base of the plant. Pull them out of the ground if you don't want them to grow.
Part 2 of 3: Stimulating Summer Growth
Step 1. Begins after the first summer flowering
It usually occurs in the middle of the season. Verbena plants often bloom very intensely, but if you don't prune them, they won't produce any more flowers over the course of the summer.
Don't be afraid to prune the plant when the first flowers are still there. By cutting it early, the flowers will continue to grow throughout the summer and fall
Step 2. Cut the entire plant a quarter of the way
To do this, use garden or hedge shears. Prune from the top, not the bottom. Within 15-20 days, new flowers and branches will appear to replace the old ones.
- You will usually only need to do this once, after the first flowering.
- Be sure to wear protective clothing, such as gloves and long sleeves, before pruning the plant.
Step 3. Continue pruning the tips of the plant lightly throughout the summer
Verbena grows very quickly, so you need to cut it often to control its expansion. To do this, cut about 5 cm from the branches of the plant where you want to contain it.
- You can do this 2-3 times per season or as needed.
- This is called plant trimming. It is used to help the verbena expand and grow thicker and fuller, preventing it from spreading too horizontally along the ground and from forming holes.
Step 4. Remove leaves with mold
Verbena resists disease well, but if summer has been humid, remove parts of the plant covered in powdery mildew if necessary. Look for white, dusty spots on the leaves. If you see them, peel them off or cut the branch they belong to.
- Be sure to disinfect the shears with alcohol before and after pruning a diseased plant.
- Apply a fungicide or neem oil to the verbena to completely get rid of the mold.
Part 3 of 3: Remove Dead Flowers in Autumn
Step 1. Try to remove dead flowers from the plant about 4-6 weeks before the last frost
Consult an agricultural calendar or weather service to find out when the last frost occurs in your area. If you don't know the dates, remove the flowers in the first days of fall.
This removes dead flowers, dead branches, and seeds so that the plant produces new flowers the following year
Step 2. Cut off dead or wilted flowers at the base
When you notice them starting to wither, fade, or die, cut them off at the base. You can also turn the stem and peel off the flowers or seeds with your hands. Throw them in the compost bin or trash.
Step 3. Remove the seeds if you don't want the verbena to spread naturally
The integuments (or "heads") are the uppermost parts of the flowers and protect the seeds after the petals have died or fallen off. By removing them, the plant will not be able to spread its seeds. Leave them in place if you wish vervain to spread in your garden.
- If you let vervain spread naturally, you won't be able to control its spread, but the new seedlings will be more resistant to climate and drought than specimens born from pruning cuttings.
- Some people prefer to leave the seeds over the winter to give their garden more color. If you like the way they look, cut out any new seedlings when you prune the plant in spring.
Step 4. Avoid pruning the plant too much in the fall to help it survive the winter
Removing dead flowers is helpful, while you should avoid cutting the verbena too much. Resume pruning with the arrival of spring the following year.
Step 5. Apply mulch around the plant to protect it during the winter
Once all the dead flowers are removed, add a layer of mulch around the base of the verbena. You can use a product that contains wood chips, dead leaves, or compost. This way you will protect the plant for the winter.
