Tips for helping your garden weather a hailstorm and its aftermath

Ray Daugherty
3/26/2025

The National Weather Service has issued a rare severe hail warning for this evening for Puget Sound.  Here are some tips for helping your garden weather a hailstorm and its aftermath.

1.) Prepare by protecting the most vulnerable and highest value plants. Cover plants that produce a single flush of growth each year (ex. Peony and Hosta) with plastic buckets or totes. Move prized containers, especially woody plants, under decks or place them near the truck of larger evergreens to protect them from the harshest hits. Avoid tarps and blankets as they will simply become nets that hold the hailstones; the weight of which may cause branches to snap!

2.) After the storm passes triage your response. Large hail stones will damage every plant in your garden and how damaged a particular plant is can be hard to ascertain. In general, deciduous and evergreen broadleaf shrubs and trees are most easily damaged. Hail may snap off small twigs and may shred or strip them of their leaves. More importantly, it may bruise or strip bark from sections of their stems. Conifers may experience similar, but usually less dramatic defoliation and stem bruising. Groundcovers and perennial flowers may be absolutely shredded or hardly touched. The wounds (bruises) on the plants stems are what plant pathologists call “infection entry points.” Inspect your plants looking for them. When a plant is quite susceptible to severe disease in our region and has lots of wounds it becomes a higher priority for after care. Knowing this, here is how to proceed when recovering from a hailstorm.

Step 1: Clean up – Blow or gently rake away the debris and compost it. We will save pruning for later. Leaving this debris, especially if it is touching the plant, becomes a potential source for several diseases.

Step 2: Treat plants that are known to be susceptible to bacterial or fungal disease with a copper-based fungicide (aka Modern Bordeaux Mixture replacement) to protect them from the infection. One or two applications should be sufficient because this is meant to protect the plant for a few days until it can plug the underlying cells with disease resistant chemicals.

Step 3: Judiciously prune away damaged plant parts. Don’t overdo. The more foliage you can leave on the plant, the faster it will recover.

Step 4: Cultivate un-mulched spaces and fertilize. Large hail stones may compact the surface of exposed soil. Using a cultivating fort to loosen the top inch or so of soil. If you have not already done so, fertilize your garden. As the plant begins to regrow, it will need lots of nutrients for all its new leaves and to create the protective response chemicals it needs.

3.) Be thankful this is happening in spring and Learn acceptance. Our plants have all summer to recover from this. Having done what you can, accept mother natures outcomes. Use any changes she brings to your gardens as opportunities.