What’s wrong with my Heuchera?

June 24, 2016

Heucheras have become a staple of garden and container designs across the Pacific Northwest. Caramel, plum and lime foliage that provides year round interest just can’t be beat. One of our favorite things about their foliage is the way it can change with the seasons. Cool fall and winter weather bring on rich saturated colors, new spring new growth is fresh and vibrant but what happens when the onset of summer brings spots and problems?

Heuchera Rust

Although Heucheras are typically trouble free plants here in Washington, they can be prone to a few pests and diseases. While walking the garden recently we spotted the signs of rust, a fungal disease found on Heuchera and its close relatives. Symptoms first appear as depressed brown spots on the topside of the leaf. When you flip the leaf over you will find a raised bump with orange rust spores.

Heuchera Rust

Causes

Like many fungal problems in the Pacific Northwest, air circulation, humidity and moisture play a big roll in rust infections. Got a moist spot in the garden with bad airflow? Say hello to fungal problems! We typically see it in late spring or early summer around the Seattle area when things are moist and humid.

Prevention and Cultural Controls

Although this fungus is not likely to kill your plant the damage to the foliage is quite unsightly. The good news is that this rust does not spread to other plants in your landscape. But what do we do to protect our Heucheras?

To fix the problem we must change the circumstances that led to it. A good landscape design and irrigation program along with proper sanitation will go a long way to preventing such problems.

  • Increase airflow in your garden by not spacing plants too closely together.
  • Utilize a drip irrigation system instead of overhead sprinklers to reduce moisture on the foliage.
  • Watering overhead should be done early in the morning allowing time for the foliage to dry out during the day.
  • Inspect new plants for rust before introducing to your garden.

Once you spot rust the best approach is to remove the infected foliage.

  • Remove infected leaves and discard them instead of composting.
  • Practice good garden hygiene by cleaning your tools and gloves once your done.
  • Prune out and clean up dead foliage to keep the fungus from over wintering.
  • Prune off old tattered foliage in late winter increases airflow around the stem and allows fresh new foliage to take its place.

Disease Resistant Alternatives

Unfortunately there are no conclusive lists on Heuchera cultivars resistant to rust.  Because the Heuchera cultivars we find in garden centers are hybrids from up to five different parent species we see great variation in disease resistance and plant performance. We have had good luck with ‘Obsidian’, ‘Berry Smoothy’, some of the silver-leafed varieties like ‘Silver Scrolls’.

What have been the best performers in your garden?

Do you have a plant that you are having problems with?  Post your question below and we may just answer it in one of our upcoming posts.

Garden on!

 

 

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