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Perennials/Hypericum calycinum


Hi Tom.

This spring I planted a hill with junipers and had some space at the bottom so I planted three rows of ST. John's Wort. Before planting I turned over the whole hill and amended the clay soil with compost(not sure if I used enough). I live in central Virginia and we have had a lot of rain and everything seems to be growing and spreading.

I just got back after a week away and noticed one ST. John's plant turning brown. It also looks like the some other St. John's wort have a reddish orange or yellowish tone to the leaves. The research I originally did said these plants are supposed to be problem free.

Please tell me what you think and if there is something I can do. I was wondering if to much rain is causing a problem. I haven't been able to find anything on the net that addresses this so thanks in advance for any advice you can supply.

Hi Joe,
Thanx for your question. Sorry it took so long to get back to you.  I have looked everywhere to see if I could find anything on this.    These plants are pretty much carefree but occasional can be victims of several diseases.

One cause could be rust.  It is brownish in hue and eventuallya kills the whole plant.  It is a fungus.  Remove all affected plants and treat the area with sulfur compounds.  You can find the anti-fungal sulfer compounds at your local nursery.  Another possibility is nematodes, although less likely.  Remove affected plants and treat the ground with diluted fish emulsion.  Still another cause is the clay has become too dry.  If you've had really hot, dry conditions, a good soaking once a week should help revive your plants.  If the clay is not draining well, that can cause root rot too.  I hope this helps.


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Tom Alonzo


I have been a gardener for 20 years with perennials both growing from seed and from nurseries. I went through the Master Gardener Program from Kansas State University Cooperative Extension Service and I answered questions on the Hotline a few years ago for the Wyandotte County Kansas Extension Service. I have also lived in the Florida, California, Hawaii, Arizona, Texas, Kansas and Missouri and am experienced with a variety of climates, soils and weather conditions.


I have been growing perennials for over 20 years now. I am self-taught mostly except for a master gardener class. I have experimented with all kinds of perennials including many that are not common to my area. I have read hundreds of books and grown hundreds of varieties of plants and hope to make it a business some day. I have become versed in botanical names and growing conditions and what I don't know off of the top of my head I can usually easily find in my vast array of research material and botanical and horticultural contacts. I especially enjoy experimenting with growing plants out of zone.

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