Most brunnera problems trace back to just three main issues. The top three are leaf scorch from too much sun, slug damage in wet weather, and foliar nematodes in older clumps. Each one has clear signs and easy fixes that I have used in my own shade beds with great results over the years.
Brunnera leaf scorch is the most common issue you will ever see with these plants. The signs are easy to spot once you know what to look for in your garden. Brown crispy edges show up along the leaves first. Then the brown spreads inward as the heat builds through the day.
When I first moved a clump of brunnera to a new spot, I made a big mistake. I put it in a spot that got four hours of afternoon sun. Within two weeks, the leaves looked toast. I learned to move it to a shadier spot right away. The plant pushed out fresh new leaves within a month.
Most brunnera problems trace back to bad siting or stress, not real plant diseases. Plants in the right spot rarely run into trouble at all. Stress from heat, drought, or root damage makes brunnera weak. Weak plants then fall prey to pests and other issues that healthy plants shrug off with ease.
Brunnera slug damage is the next big issue, mostly in wet springs. Slugs love the soft new leaves that push up in March and April each year. You will see ragged holes in the leaves and shiny slime trails on the ground. The damage gets worse on cool, damp nights when slugs are most active.
I have found a few tricks that work well for slug control in my beds. Iron phosphate bait is safe for pets and works great on slugs and snails. Sprinkle it around your plants in spring. Beer traps also work well if you do not mind the mess. Hand picking at night with a flashlight gets the big ones too.
Brunnera foliar nematodes are the third issue and the worst of the three. These tiny worms live in the leaves and cause brown wedge shaped patches between the veins. The damage spreads up the plant as the season goes on. Older clumps in damp spots are most at risk for this issue.
The fix for nematodes is to remove all the bad leaves right away. Cut them off and toss them in the trash, not the compost pile. Water at the soil line and not from above to stop the spread. In bad cases, dig up the clump and start fresh with a clean plant from a trusted source.
To stop brunnera problems before they start, pick the right spot from day one. Plant in full shade or part shade with good rich soil. Add a two inch (5 centimeter) mulch layer to keep the roots cool and moist. Water during dry spells but do not soak the leaves.
Walk through your beds once a month to check for issues. Look at the leaves up close for early signs of pests or disease. Remove dead leaves and debris from around the base of each clump. This good habit will keep your brunnera healthy and pretty for many years to come.
Read the full article: Brunnera Plant Growing and Care Guide
