Q.My spirea double play pink planted 80 days has black leaves; is it from iron?
My spirea pink double play were blooming ang looking so healthy, their leaves were such a pale green I thought they needed iron so I gave them some 🙁 hope I didn’t kill them. I’ve been feeding them once a week with miracle grow until established — I was told 90 days is that right? They’re still bushy but are thinning; what can I do? I love these bushes!
Certified GKH Gardening Expert
This looks like a combination of nutrient burn from overfeeding, soil being too acidic, possibly from using iron AND high nitrogen fertilizers together, and it looks to, also have a fungal infection. This is normally caused by overwatering, which is common when attempting care of a newly planted plant.
What I would do is only feed once per month. Instead of using iron, try using WETTABLE SULFUR instead. I would also apply a handful of DOLOMITIC LIME per plant to help balance out the pH from treatment. Since there is mulch, you will only want to water when the soil is completely dry down to about 5 or 6 inches. This will prevent overwatering and future infection. You can also try pre-made fungicides. This article will help: https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
