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Duchess of Dirt: Water - too much of a good thing for some plants

Leslie Cox
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This grouping of drought-tolerant plants looks great in the summer, but did you know such plants can drown in conditions like the ones we are experiencing this fall? Photo by Leslie Cox

Leslie Cox

Special to The Record

Rain! Whew. The garden could have used this moisture in the summer, not now the plants are in winter dormancy. But consider the torrential rainfall as an early warning for gardeners.

Who lost plants last winter? We can certainly attribute some of the losses to the cold snaps and late snow in February – that frozen white stuff which hung around for ages. Admit it. There are a few of us pushing the Plant Zone number for our region by including a few tropical heat-loving plants in our landscape. As certifiable plantaholics ourselves, we definitely push the envelope on what is deemed “safe to grow and survive” in Black Creek, we suffered plant losses too.

But cold may not have been the culprit for all plant losses, which brings me back to the rainfall warnings. Some plant demises were very likely caused by drowning.

Sound strange? Not at all. While all plants need water in order to survive, there is a range of different needs in the moisture amounts. For instance, aquatic and bog-loving plants enthusiastically revel in lots of moisture. On the other hand, drought-tolerant plants, such as sedums, yuccas, black-eyed Susan, and a host of others, are not so tolerant of being doused by buckets of rain.

Did you lose any drought-tolerant varieties last year? Perhaps you blamed the summer drought, reasoning the lack of water was even too much for this type of plant. Solid reasoning, but is it the truth?

Who is a fan of the CSI shows on TV? Well, even if you aren’t, you have to get into investigative mode. And right now, in the middle of all this rain, is an ideal time. Don your wet gear and go check on your plants.

You are looking for clues. Are any of your plants are sitting in a puddle of water… even just the smallest of puddles? Depending on how much time has elapsed since the last rainfall – and the amount of rain that fell – even small puddles of water around a plant can be detrimental to its survival. Depending on the plant, of course.

I make regular forays into the garden through the winter. Not only am I looking for uplifting botanical scenes deep into fall and the dead of winter, I also keep an eye open for anything out of the norm – like puddles around plants. Any that I spot, I will re-visit in an hour or so to see if it has drained away properly. (Truthfully, there are some advantages to having a gently sloping garden!)

This is the CSI part. You are hunting for “The Silent Killer” of plants: crown rot. And crown rot happens when the crown of a plant is sitting in water for extended periods of time.

Do not fall into the “lazy detective” category by thinking your plants are fine because you planted them a little above the level of the surrounding soil. Be proactive in your investigations.

Even if you do not mulch the beds regularly – thus raising the soil level – plants can sink down as they pull nutrients out of the soil.

If you should find any plants sitting in a puddle, a quick fix is to dig a moat around the plant. Size of the moat will depend on how big the puddle but be careful of the roots. You want to encourage the water to drain away from the crown of the plant.

The moat also serves as a reminder the plant must be re-positioned in its spot come spring. Just remember to add humus-rich compost to the hole to encourage better drainage. The more drought-tolerant plants would benefit from some sand worked in to help drainage.

Happy sleuthing!

Leslie Cox co-owns Growing Concern Cottage Garden in Black Creek. Her website is at www.duchessofdirt.ca and her column appears every second Thursday in the Record.