Softwood Penstemon Cuttings

How to Take Softwood Penstemon Cuttings in Late June and July

If you’re looking for an easy and rewarding way to propagate colourful perennials for your garden, Penstemon cuttings are an excellent choice. These vibrant flowering plants root readily from softwood cuttings taken in late June or July, and with a little care, you can have strong young plants ready for autumn planting or potting on for spring displays.

Why Take Penstemon Cuttings

Penstemons are ideal candidates for softwood cuttings — the type taken from the current season’s young, flexible growth. These cuttings root quickly, require minimal equipment, and reward you with plenty of new plants that are genetically identical to the parent, preserving colour and growth habits.

Step-by-Step Guide to Taking Penstemon Cuttings

1. Choose the Right Stem

• Look for non-flowering stems with healthy, vigorous growth.
• If all stems have flowers, it’s fine to select a flowering one — just snip off the flower before preparing the cutting.
• Cut the stem just below a leaf joint or bud — this ensures a clean, firm base that resists rot and encourages root development.

2. Prepare the Cutting

• Cut a length of stem about 8–10 cm long (3–4 leaves from the top).
• Remove the lower leaves, leaving 2–3 leaves at the top.
• If leaves are large, trim them by half to reduce moisture loss.

Rooting Methods

You have two simple methods to choose from:

Option 1: In Water

• Place the cutting in a glass of clean water on a windowsill.
• Keep it out of direct sunlight and change the water every few days.
• Roots should appear in about 10 days.

Option 2: In Compost

• Fill a clay pot with a 50/50 mix of John Innes No. 1 seedling compost and perlite or vermiculite.
• Insert the cuttings around the rim of the pot — they tend to root more successfully this way.
• Clay pots are ideal because they absorb and release moisture, helping to maintain humidity around the cuttings.

Top Tip: Create a mini greenhouse by placing the pot inside a clear plastic bag. Blow into the bag to gently inflate it, then tie it at the top. This boosts humidity and reduces the need for frequent watering.

Aftercare and Growing On

• Place the pot on a bright windowsill, but avoid harsh, direct sun.
• Keep the compost consistently moist, not waterlogged.
• You should see roots poking through the bottom of the pot within 2–3 weeks.
• At this stage, carefully unpot and transfer each rooted cutting to a 9–10cm (100mm) pot, again using a seedling compost mix.
• Grow them on in a sheltered spot or under glass, and they’ll be ready for planting out after a couple of months.

Swap, Share and Grow

If you’re a GardenAdvice Member, don’t forget you can take part in our autumn plant swap or join the Root, Shoot & Share scheme, where we root and send out cuttings directly to you.

Penstemons are among the easiest softwood cuttings to propagate — ideal for beginners and experienced gardeners alike. With just a handful of stems and a few weeks of patience, you’ll have a flush of new plants ready to brighten your borders year after year.