Generally speaking, delphiniums are pretty low-maintenance additions to any flower bed. However, these stunning perennials can be a bit finicky when it comes to their health. To keep those leaves from turning yellow, your delphinium needs the perfect spot in the yard and plenty of nutrients to stay happy.
Delphiniums and Yellow Leaves
Delphiniums (or “larkspur” as some of us call them) are sun-worshippers. They need a spot that gets full sun to really thrive. Since they are “heavy feeders,” they also require soil that is rich in nutrients. This means you’ll need to fertilize regularly or mix in plenty of compost. If the plant isn’t getting the “food” it needs, you’ll likely end up with puny blooms and—you guessed it—yellowing leaves.
If you notice your delphinium leaves turning yellow, it’s usually due to one of these three culprits:
- The wrong location
- Nutrient deficiency
- Poor drainage (waterlogging)
The Wrong Location
One of the most common reasons for yellow leaves is simply where the plant is sitting. Delphiniums need full sun to reach their full flowering potential. They also prefer soil that is loose, moist, and rich in organic matter.
If the spot is too shady or the soil is heavy clay, the plant is going to struggle, and it’ll show its unhappiness through yellow foliage. If this is the case, your best bet is to transplant it to a better spot. When you move it, be sure to enrich the new hole with plenty of fresh compost.
Nutrient Deficiency
If your delphinium is in a sunny spot but the leaves are still turning yellow, it’s likely crying out for nutrients. This usually happens if the soil is lacking humus or if you’ve fallen behind on your fertilizing schedule.
To help the plant bounce back and get those leaves green again, you’ll want to use a fast-acting fertilizer. While organic options like compost are great for long-term soil health, they work too slowly to fix an immediate deficiency. Reach for a liquid fertilizer instead to give the plant a quick boost.
Waterlogging
If the yellowing is caused by root rot from standing water, I have some bad news: the plant is usually beyond saving at that point. Always make sure your soil drains well to keep those roots healthy!
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