Welcome to Bad at Plants, a new column in which plant expert Maryah Greene, of Greene Piece consulting, answers your questions about plants, so that we might all become at least slightly better at keeping them alive.
“Is there anything you can do to save/revive a plant whose stems have turned brown? I am growing a rosemary plant in a terra cotta pot outside (with a drainage hole), and I think it didn’t like the near-constant rain we were getting last month. The stems are brown and the needles are looking sickly. Can I bring it back to health?”
It sounds like your plant might be suffering from root/stem rot, both of which are often caused by overly wet soil and/or improper drainage. Signs include the roots or the stem feeling soft, wilting, and turning brown or black. Unfortunately, once you notice root/stem rot taking over your plant, it’s VERY difficult to revive your plant.
I like to compare root rot/stem rot to split ends and hair care. Split ends can’t be repaired once the hair splits, despite what conditioners try to get us to believe. However, you can take measures to prevent it from happening, like consistent trims (or trimming your plants), conditioner (fertilizer), and changing your wash schedules (or watering schedule). Hair doesn’t like to stay damp and soggy — it has to dry to absorb all the moisture and nutrients we give it during a wash. Same for plants.
I can sympathize: I left my small basil plant outside one day last month, since it was sunny, and I live in a basement. I figured it would like some sunlight for a bit. I didn’t expect the intense downpour that came later while I was at work. When I returned, the pressure of the rain had made the soil overflow in the pot, and the basil stalks were completely bent in half and laying on the ground. It was a goner. If I would have left it outside to “recover,” the leaves and newly exposed roots would have simply fried in the sun. (Direct sunlight hitting water on some plants’ leaves makes them burn. Think of it like the ant-and-magnifying-glass trick.) Some plants (like ferns, and palms) can take the rain, but sadly, not basil, and not rosemary.
Rosemary is found on cliffs/hills in nature, so it’s used to rain water constantly draining from the soil. Planting it in a small planter can be tricky. I’m going to assume it’s also a no-go for your rosemary, especially because herbs are so temperamental. They intimidate me, but more power to anyone who can deal with their drama.
More broadly, I think it’d be useful to take the category of brown leaves and stems and break it into two. There are brown, super-soggy, droopy leaves, and then the other side of that is brown/yellow and crunchy/crispy. These are two different problems. Soggy means too much water — either too much at once, or too often. The other side of brown plants is crispy, crunchy leaves, and that’s too much sunlight, where the sun is sucking the life out of the plant. From there you can figure out what steps to take. For brown and crunchy, move it away from the light. It’s trial and error: Back it away from the light source by a couple feet to see if that makes a difference.
Burned leaves/plants are much easier to revive over plants that receive too much water, mainly because it’s more of an external rather than internal issue. Dampness and water are absorbed by the roots. Burned plants have some scorching on the leaves, but the roots are usually okay since they’re buried. That being said, a burned plant needs the same two things a sunburned human needs. 1) WATER! Get it on a regular watering schedule as soon as possible. 2) Shed the burned layer. Super gross that we peel when we get sunburned, but our plant wants to do the same thing. Cut off anything burned or yellow ASAP. This promotes new growth on the plant.
For soggy plants, water them less often. If you’re on a 7-day schedule, move to 10 or 11. If you’re giving it too much water at one time, maybe cut back. You do want to make sure you’re drenching your plants, but only when they’re completely dry. If the soil is moist whatsoever, don’t even touch it. Also, be sure to have a hole at the bottom of your planter OR a lining of rocks/stones/pebbles at the bottom of the pot to act as a drainage layer. Keep your plant on a consistent watering schedule and when you notice intense/heavy rain outside, BRING YOUR PLANTS INSIDE!
You also want to think about the time of year in your plant care. Think of August as the extreme for heat and direct light, and think of January and February as the extreme for cold and no light. It’s a really crappy time to have a plant.
Do you have questions for Maryah? Send them to firstname.lastname@example.org and we’ll try to get you an answer.