What To Do When a Penstemon Isn’t Flowering

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Willie writes on small engine repair, landscaping, and lawn care. He owned a professional lawn care business in Alabama for almost 10 years.

3 Tips To Make a Penstemon Flower

Penstemons are known for their amazing colorful flowers, so it will strike you as unusual when they are not blooming as expected. If your penstemon isn’t flowering, you can try a few long-term and short-term fixes that will help your plant.

To understand the fixes I propose below, you should keep in mind the typical conditions that penstemons require to thrive. If the environment around your plants does not fulfill all the conditions, your plants will likely experience issues, like flowering late or not flowering at all.

1. Put Them Under Sunlight

Penstemons enjoy the sunlight. Generally, you should place them somewhere they can receive direct sunlight for hours so they can thrive properly. You can also put them in partial shade, but full sun is better.

If your penstemon isn’t flowering yet, it may be because it’s not getting enough sunlight. If you have placed or planted your penstemons in a place that doesn’t receive direct sunlight, you need to move them.

Potted penstemons are easy to manage since you can move them from wherever they are.

However, if you have planted your penstemons in a flower bed in your garden, you need to figure out a way to help them receive more sunlight. You may need to replant them at worst, but only if the time is right (source).

2. Add Fertilizer to the Soil

Penstemons can grow or even thrive in drier and leaner soil (source), but most varieties need plenty of nutrition during the blooming season. Your plant needs extra energy to grow flowers, so it’s understandable that nutrient-poor soil is not ideal.

To help your penstemon flowers bloom, you may need to add more fertilizer to their soil. Adding nutrition ensures that your plants have everything they need to produce new flowers, provided every other condition is met.

You can add fertilizer without repotting or replanting your penstemons. To add granular fertilizer, you must dig furrows into the soil to ensure the nutrition reaches the roots.

Once you place the fertilizer in the furrows, you can water the soil slightly to encourage the material to go deeper. As for liquid fertilizer, you can add it with water.

3. Cut Your Penstemons Back

While the previous steps can help your penstemon flower very soon, this one will ensure that your plant blooms in the upcoming season. If your penstemon did not bloom during summer, you can prune the plant to help it produce flowers next time.

Penstemons are perennials, meaning they have a blooming season, typically late spring and early summer. Then, during fall and winter, they die, only to come back and bloom the next spring, and the cycle continues.

During the “off-season,” it’s recommended that you cut your penstemons back, to help encourage blooming next season. While pruning may seem like it’s killing your plants, it’s actually refreshing and rejuvenating them, so you shouldn’t hesitate to cut a significant amount of stems back.

You can choose to prune your penstemons once or twice a year. Some recommend only pruning them once in the winter, once you’ve made sure they are completely dead. Others recommend pruning them in mid-spring to give an additional boost to help them direct their energy toward flowering.

What Else Prevents Penstemons From Flowering?

The causes I described above have solutions, but a few other issues might not be within your control.

Your Penstemons Might Be Too Old

Penstemons are perennials, so they have a certain cycle they go through every year. However, these plants don’t last too long, so after a few seasons, they will die permanently.

Your penstemon may be toward the end of its life, which means it has much less energy to produce new flowers. As a result, it will not bloom during spring or summer and will likely die in the fall. In these cases, there’s nothing you can do for this particular plant.

Unusual Weather Patterns

If the temperatures in the spring and early summer are lower than usual, your penstemon will not be able to bloom in its typical blooming time (source). This may cause you to worry, but once the temperatures rise, you will notice that your plant will flower like it always does, just a bit late.

What To Keep in Mind When Caring for Penstemons

Here are some additional tips you need to keep in mind, which can help you care for penstemons in different conditions.

Penstemons require well-drained soil. Plant them in a type of soil that does not retain moisture; otherwise, your plants might die or wilt very soon.
Propagate penstemons using cuttings. Considering their relatively short life, you can propagate penstemons by taking cuttings, preferably during late spring or summer.
Temperature-wise, penstemons are pretty diverse, as some varieties can tolerate the cold better than others. Generally speaking, they thrive in USDA zones 4 to 9.
Some penstemons reach more than 3.2 feet (1 m) tall. The varieties with larger flowers may need staking to stand upright.

Final Thoughts

Penstemons are perennials, so they flower every late spring or summer and then die during fall and winter. However, sometimes they may not bloom because they require more sunlight or more nutrition or simply don’t have enough energy.

You can place your penstemons under the sun and add fertilizer to the soil to help them flower. Additionally, you should prune them once or twice a year to encourage growth. However, if your plant is too old or the weather is unsuitable, there’s nothing you can do.