Why do the leaves of my Snow on the Mountain (Bishop's Weed) turn "rusty" in certain garden areas? I live in the Midwest (Wisconsin) and this happens every year. Formerly attractive borders look lousy.
This is quite common for Bishop's weed in mid-summer. The more sun a plant gets, the more likely it will have browned edges. Keeping the soil moist will help but the truth is, the plant doesn't like hot weather. If the browning is extensive, consider using hedge shears to trim off unsightly foliage. Nicer foliage returns with cooler weather.
My Bishop's Weed had almost filled my entire 15' x 4' bed by last year and this year only a few spindles came up! I planted it about 4 years ago and it has filled in more and more over those years until this year! Will it all come back next year? Or do I need to replant some?
You may have had some drought that needed water. In any case, I wouldn't count on it coming back, so some additional plants would be in order. You may want to topdress the soil with some compost to give it a boost.
Got a very large semi/wooded slope bordered by concrete on three sides and a creek on the other. Can I sow Bishop's weed seed directly to the ground? It would take 6 months clear this area for traditional planting. I want a groundcover that I can sow and forget.
Yes, they will take over very rapidly from directly sown seed. This article will help you to grow these: https://www.gardeningknowhow.com/ornamental/groundcover/snow-on-the-mountain/snow-on-the-mountain-plant.htm
Is there something preventative I can use to stop that rust? My beautiful bishops weed or snow on the mountain gets rust on it every year all along my fence and in my yard and it doesn’t matter where it's planted at so I know it’s must be something in the soil and I do not know how to prevent it. Please help. I can’t send you a picture of it yet because it hasn’t happened yet I’m trying to avoid it.
You can spray you plants with neem oil regularly to prevent it or remove the leaves as soon as you see it.
Our experts say rust thrives in a wet environment, so don't overwater your plants. Also, make sure they have good air circulation inside the branches and around the plant itself. This will help it dry their leaves faster.
I have a very large steep front slope—sparse evergreens and many daffodils plants. I would like to plant bishops weed on the top quarter and let it spread. I don’t want the flowers in particular to be harmed.
Bishop's weed has shallow roots, plus daffodil bulbs will come up through just about anything so it shouldn't bother your bulbs.
It starts turning brown in July-does it need more water?
If the weather is hot and dry, it will need more water. Here are its care tips:
Do I cut off flower tops and use them? Or do I have to dig some up to move it?
This aggressive plant grows from rhizomes. Your best bet is to dig up clumps of it to transplant. It won't mind if the rhizomes get a bit cut up or broken - it should still "take" wherever you plant it.
Here are some tips:
https://www.gardeningknowhow.com/ornamental/groundcover/snow-on-the-mountain/snow-on-the-mountain-plant.htm