Q: Our Autumn Blaze maples had iron chlorosis last year. An article you wrote prompted us to take action. We bought Medicap iron capsules made for trees online. Following the directions, we drilled holes and pounded the capsules into the trunks of our five trees. Here's a photo of the worst tree we had. You can see it's still lighter but not nearly as yellow as the year before. Our other trees that were slightly less chlorotic last year didn't turn yellow at all this year. The photo on the left is July 2017, the one on the right July 2018. - Deb Faber, Fargo.

A: Thanks for the wonderful before-and-after photos. Even though there's still a little yellowing, we can see how much healthier, greener and larger the leaves look a year after treatment. Besides the improvement in color, the overall health of the tree looks better.

Yours is a good example of one of the three methods of applying iron to a yellowed, chlorotic tree. Chelated iron, which is iron that's more readily absorbed by plants, can be applied to the foliage, to the soil and root system or into the trunk through injections or capsules.

Q: Having read your article about iron chlorosis, I wanted to comment that I did everything recommended for my Amur maples, but it was too little too late. I lost four of the five and it was a big project trying to save them. Now my one happy maple gets a shot of iron from Paul Bunyan Tree Service. I planted two Mountain Frost pears, which also have needed iron, but hiring Paul Bunyan once a year is more effective than when I tried to apply the iron myself. It's a great service in our alkaline soil. - Barb Anton, Fargo.

A: Thanks for your comments, and for bringing up two great points. First, it does seem there's a point of no return, when iron deficiency is so great that it's too late to resurrect a tree. Severe iron deficiency weakens trees, making them easily susceptible to winter injury and attacks by pests and disease. Early detection and treatment are important for best success.

Second, thanks for reminding us about professional tree services that offer iron applications or injections and are a good option for those who'd rather not tackle it themselves.

Q: What are the round green balls growing on my potato plant? - Karen Moszer, Fargo.

A: The round balls that sometimes form at the tops of the plant are the potato fruits. Under the right conditions, pollination is successful within the potato flowers and fruits develop that will eventually contain seed.

Potatoes are in the same family as tomatoes, and the potato fruits look similar to small green tomatoes, but they aren't edible. Although it's common to see potatoes flowering, it's slightly less common for fruits to form, as it often depends on the year and the weather. Whether or not the seed balls form, or whether or not they're removed, doesn't seem to affect size, quantity or quality of the underground potato tubers.

Q: Which flowers would you recommend to attract and help bees? - Birgit Preuss, Fargo.

A: Top perennials that are winter-hardy in our region and are bee magnets include monarda, tall garden phlox, Joe-Pye weed, Russian sage, liatris, rudbeckia, coneflower, gaillardia, sedum and agastache. Annuals include marigold, zinnia, blue salvia farinacea, cleome, heliotrope and the herbs borage and mint.