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Penstemon, otherwise known as beardtongue, is a colorful plant that has become very popular in American gardens. Typically, you need to propagate it using cuttings, but this isn’t something you can do all year long.
It is too late to take penstemon cuttings in the late fall. By this time, the cuttings won’t be fresh and will not be able to root fast. As temperatures drop and days get short, the chances of these hardwood cuttings rooting are much lower.
The best time to take penstemon cuttings is in late spring or early summer. Keep reading to learn all about propagating penstemon and the best time to do it. I will also include a guide to help you with the process and offer additional care tips.
Why You Shouldn’t Take Penstemon Cuttings in Late Fall
After early fall, penstemon cuttings are very unlikely to root, considering the temperatures drop and the sunlight is scarce. Fall and winter are generally not ideal for taking cuttings of perennials because the low temperatures can be very harsh on newly formed plants.
Penstemons are perennials, which means they bloom and grow during the spring-summer season, and then die during winter. These plants, in particular, do not live very long, only lasting a few seasons, so you need propagation to ensure you keep having these wonderful colorful plants in your garden.
Propagating penstemons involves cutting segments of relatively new stems and then planting them in a separate pot, where they are supposed to develop roots and create a new plant.
The process of propagation depends heavily on the state of the cuttings. These shoots should be mature enough to have the energy to produce their own roots, but they shouldn’t be turning into hardwood either. You must find the perfect time to allow your cuttings to thrive and root.
Generally, you have a pretty wide window of opportunity to propagate penstemons during the warmer months. However, after a certain point, you cannot take cuttings anymore because the chances of them growing into a new plant are quite slim, considering the colder weather.
When Is the Best Time To Take Penstemon Cuttings?
I could not tell you an exact time or day for taking penstemon cuttings since every plant is different and every season is unique in terms of temperatures and sunlight.
However, there are some general rules you can follow that will help you decide when to take the cuttings for them to root as soon as possible.
Late Spring to Early Summer
The best way to propagate penstemon is using softwood cuttings. These cuttings come from a fresh new stem and can root much more quickly since they have more energy than relatively older stems.
Most perennials use softwood cuttings for propagation because they are faster and more reliable than mature stems.
It’s ideal to take softwood cuttings when the plant is growing. Growth typically occurs during the spring or summer seasons. Therefore, the best time to take penstemon cuttings is between late spring and summer (source).
At this exact period, the stems are still fresh and soft, so they are likely to root quite fast, but they are also mature and resistant enough to survive the process. If you take the penstemon cuttings around late spring, you can plant them outside as individual plants by mid or late-summer that same season.
What About Early Spring or Fall?
With the arrival of spring, you may be excited to grow and nurture new plants, but it can be too early for propagation. New stems that emerge during this time of the year are very soft and weak, making it difficult for them to develop roots.
If you want to take cuttings in late summer or early fall, you still have pretty good chances. Cuttings taken around early fall are typically semi-hardwood, so they won’t develop the root as fast as the ones taken during spring.
Still, they can survive during winter and then bloom and grow in the next spring.
However, you need to store your cuttings indoors during winter. This ensures that they won’t be exposed to low temperatures and excess humidity, which are common in a typical winter outdoor environment.
If the conditions are right, the cuttings will root more slowly, but you will have new penstemons when spring comes back.
How To Take Penstemon Cuttings
Once you’ve chosen the best time to take penstemon cuttings, you can proceed with the task. Taking penstemon cuttings is similar to the general propagation process of most perennials (source). Follow these steps:
- Prepare a good pot with drainage holes. Fill it with a potting mix and then water it so the soil is damp but not too wet.
- Prepare your cutting instrument. Preferably, you should have a pair of sharp and clean pruning shears, but you can also use any type of clean, sharp blade.
- Take the cuttings. Cut a segment from a healthy-looking, long stem at a 45-degree angle below the lowest leaf.
- Remove the extra leaves. You want to leave a couple of leaves on, but if there are more, you should remove them so that the stem directs all its energy toward developing new roots.
- Dust the cuttings with rooting hormone. This step is optional since cuttings can root without help, but if you want to boost your chances, dip or dust the cuttings in rooting hormone.
- Plant the new cuttings. Plant the cuttings in the moist potting mix and then cover them to protect from temperatures and keep them moist.
If you want to propagate your penstemons, you must take cuttings from the existing stems. The best time to do so is between spring and summer, but you can also do it later in the season.
However, after early fall, it’s not worth trying to propagate these plants since they will not be able to develop roots fast enough, and they may not resist the lower temperatures. To take penstemon cuttings, you need to cut the tops of the healthiest, non-flowering stems and plant them in a moist potting mix.