I have a large area with pachysandra growing but part of the area has been dying the past year or two. I have a neighbor with a swimming pool that has a drain near the edge of my yard. Is there a test I can use to see if they have been dumping chemicals that are killing my plantings?
Baltimore County Maryland
Chlorine tends to volatilize (evaporate), but there may be other water-treatment chemicals in pool water that are damaging to plants, especially with repeated exposure. We have a page on chlorine toxicity here, though we suggest verifying this is present in the soil in problematic amounts before attempting any mitigation treatments. https://extension.umd.edu/hgic/topics/chlorine-toxicity
A more likely cause is the combination of the overly-wet weather we experienced the past two springs along with any inundation of this soil with water from their pool. Soil-borne diseases that cause root rots prosper in such wet conditions, and Pachysandra is vulnerable to this, as are many groundcovers. Even if roots were spared, moist conditions promote other above-ground leaf and stem infections that Pachysandra can contract. The swath of the affected area in the picture suggests that an outbreak may have occurred, though this can also be showing the areas of poorer drainage. Has the tree in that image shown any signs of distress or dieback? (What type of tree is it?) Since its root system is going to be present throughout that whole area, enough of it is exposed to the same conditions the Pachysandra is experiencing, and therefore it could be an indicator of wetness being an issue. (Diseases affecting the Pachysandra won't always affect unrelated plants, so this might help narrow it down.)
Soil testing labs may not be able to detect chlorine in the soil at all, if it is even still present so long after the last pool draining. You can ask the labs if they have the ability to test for this or other pool chemicals; our page on soil testing lists some area labs, and you can also search for "environmental" testing companies. https://extension.umd.edu/hgic/topics/soil-testing
You can try a clean-up of the affected area if you wish to see if the Pachysandra will regrow. Rake out what leaves and debris you can, and you can even mow-down the few stems that are left to encourage new growth. Otherwise, trying to establish a different groundcover in that area might be prudent, assuming a pool-chemical issue isn't a play. Options for shaded areas are numerous, depending on other conditions (such as that possible wetness issue, deer, etc.), and include perennials and a few short spreading shrubs.
Alternately, perhaps the neighbor is amenable to creating a drainage pathway to direct any pool drainage away from your yard and into a catchment/filtration area on their own property.