Q: I was shocked to read in your column that you have the nonnative and invasive leatherleaf mahonia in your garden. It frequently pops up in places where it is not wanted. They require gloves to maintain and are hard to kill. Why risk passing this plant on to others? John Yntema, email
A: Sometimes beauty is in the eye of the beholder. As you observe, it’s not hard to accidentally have leatherleaf mahonia in your landscape. But some people like the bright yellow flowers and the blue-skinned fruits, which give mahonia the nickname ‘Oregon grape’. Honeybees and native bees love the early spring blooms as well. Speaking as someone who has recently been castigated on Facebook for mentioning nandina, I’m going to leave the discussion of “invasive vs. noninvasive” and “native vs. nonnative” to folks who are more knowledgeable or more fired up than me.
Q: I have this white stuff that is hard, like dried glue, in my pine straw and soil. In places, it has penetrated between the roots of my plants and I can’t get it out. Patti Weyand, Alpharetta
A: You are witnessing the natural transition of organic matter to humus. Unlike plants, fungi do not have roots: They rely on white, threadlike hyphae to digest organic material and release the nutrients it contains. A mass of hyphae is called mycelia or a mycelial mat, which is what you see in your straw. The white hyphae don’t normally attack healthy plant roots. Even so, I would rake away the straw over the mycelial mat and let it dry out. It will gradually disappear.
Q: My cast iron plants suffered damage from the heavy freeze in December. The leaves are rusty-looking. Can I cut back the damaged ones? Beth Canada, Clarkston
A: You are not alone! Every clump of cast iron plant, also known as barroom plant, I’ve spotted looks exactly like yours. But the name ‘cast iron plant’ is not undeserved. It will grow in bright light or smoky gloom. You can water it every week or you can gallivant off to Indonesia for a month, forgetting to ask someone to water your houseplant: Aspidistra won’t care either way. It laughs at freeze damage. You can clip off rusty leaves now and wait until April to see what sprouts from the ground. If your plants were healthy at the beginning of winter, they will have plenty of reserve energy stored up to make new leaves.
Email Walter at email@example.com. Listen to his occasional garden comments on “Green and Growing with Ashley Frasca” Saturday mornings on 95.5 WSB. Visit his website, www.walterreeves.com, or join his Facebook Page at bit.ly/georgiagardener, for his latest tips.