Should i prune penstemon

All penstemon varieties withstand serious illness or disease, although the plants may occasionally suffer from root and crown rot caused by fungi such as Phytophthora, Fusarium or Rhyzoctonia. According to the Pacific Northwest Pest Management Handbooks , root rot in penstemon presents itself as discolored or stunted foliage, which can eventually lead to the decline and death of the plant.

These fungi are typically present when penstemon plants are grown under wet or humid conditions, although it's possible to transmit the fungi to the plants through the use of dirty pruning shears.

Maintaining sharp, clean pruning tools helps eliminate the fungi that cause root and crown rot. Sharpen or replace the blades on your pruning shears every year or whenever they show signs of severe wear-and-tear such as nicks or pits in the metal. Scrub the blades in very hot water with a squirt of dishwashing liquid.

The University of Florida IFAS Gardening Solutions website provides several recommendations for disinfecting pruning tools, including wiping the blades with rubbing alcohol or dipping them in undiluted household disinfectant. Soaking the blades in a percent bleach solution for 30 minutes will also help kill off the fungi, but it must be thoroughly rinsed away to prevent corrosion of the metal. Take cuttings of your favourite penstemons every few years to ensure you have the next generation in place.

If you continue to fail with penstemons ensure that the soil is not waterlogged. Dig in horticultural grit to improve drainage. In spring apply a general purpose fertiliser to your mixed borders. Water freshly planted penstemons for the first summer to help them establish on a dry soil.

In autumn cut back the faded foliage by just a third to prevent windrock and then cut the remaining foliage back hard in spring after the last frost. Browse the fantastic range of fully mature hardy perennials, shrubs, ferns, grasses and bulbs to create a spectacular garden to enjoy all year round.

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Rosemoor Devon. Wisley Surrey. Bridgewater Greater Manchester. Environmentally friendly gardening. Plant health. Take part in our research. Meet the team. Shop plants rhsplants. Shopping with the RHS. RHS Christmas gifts. Help us achieve our goals Make a donation. Join the RHS today and support our charity Join now. Save to My scrapbook. Penstemon 'Alice Hindley'. Credit: RHS Advisory. Quick facts. Cultivation notes Border penstemons are easy to grow in any fertile, reasonably moist, free-draining soil in full sun or light shade.

Pruning Penstemons can become woody and leggy if they are not pruned annually. Cut 4—5 in 10—13 cm non-flowering tips in the summer. Put your pruning shears 4—5 inches 10—13 cm from the tip of the stem just below one of the nodes with leaves growing from it. Make a degree angle cut to take your cutting. Pull the bottom leaves off your cuttings. Locate the 2—3 leaves that are closest to the cut end of your cutting.

Pinch the base of the leaf and gently pull it from the stem. That way, you expose more of the stem to help promote healthy root growth. Dip the cut ends into a rooting hormone. Pour some rooting hormone into a dish and place the cut ends of the plant in the powder. Coat the exposed node where you removed the leaves as well so they will sprout new roots.

Otherwise, you could contaminate it and potentially spread diseases harmful to your plants. Stick the cuttings into a pot with a mix of compost and perlite. Take your cuttings and place the stems into the soil around the edges of the pot. You may also use a modular planting tray if you want to root more cuttings.

Water your cuttings until the potting mix feels damp. Fill a watering can with fresh, clean water and slowly pour it onto the potting mix. Let the water absorb and sink into the pot before adding more. Once you see water running out of the drainage holes at the bottom, stop watering your penstemons. Cover the pot with a plastic bag or put it in a propagator. Place 4 bamboo poles that are taller than your cuttings into the potting mix so they form a square.

Alternatively, you can keep the pot inside an unheated propagator to maintain the humidity. Keep the pot in an area without the risk of frost. If you live in an area with freezing winters, bring your penstemon cuttings inside and let them grow over winter.