Ask John

BearTools_Fotor If you have a question about gardening in the Birmingham area, ask John. John Floyd has been gardening–and learning about gardening–for more than 30 years. In addition to his day-to-day experience in the garden, John has degrees in horticulture, plant taxonomy, and plant physiology from Auburn and Clemson Universities and was Editor-in-Chief of Southern Living.

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How to cut back overgrown Cleareas Thank you 14. September 2018

Yes, but I would wait until early spring right before they start putting out new leaves.

What is the best way to treat leaf spot on Indian Hawthorn? Should you cut back the bare branches? 6. September 2018

Right now, it is probably too late in the season. In early spring I suggest you treat with Bayer Three-in-One Tree and Shrub that you apply around the plant for general all season control.If want to treat now please call Dr Jacobi at the Hanna Center at the Birmingham Botanical Gardens for his specific recommendation at this time of the year as I have no idea.

What is the chemical that slowes plant and shrub growth? 6. September 2018

They are called growth retardants but there is not one that works for all plants. If you want to use one I suggest you check with Dr Jacobi at the Hanna Center at the Birmingham Botanical Gardens.

how to drastically prune Needle Point Holly 31. August 2018

Needlepoint holly responds well to drastic pruning but I would do it in late winter. You can cut them literally to with in a foot off the ground and a new shrub will grow. You can shaped and sized the pruned plant as it grows out how you desire. Remember that these hollies are generally 8 to 10 feet tall at maturity if left unpruned.

Do you think that ANISE Shrub would be ok in our climate..Full sun until 2pm 4. August 2018

Basically they light part sun to high filtered shade to not have the leaves that look like they are washed out-john

Is it too late to prune Weigelia? 2. August 2018

No, but just remember you are cutting off spring blooms when you prune it.

Hi John, Help! Some pest is attacking my perennials. I have noticed a white, gummy residue on the stems of my black eyed susans, cone flowers, quince and gardenias. The leaves have holes in them as well. We have tried Neem oil but I’m not sure it’s working. Any ideas as to what this pest is and how best to fight it off? Thanks. 13. July 2018

The residue you describe is probably a spittle bug but they are probably not the biggest cause for your troubles. My first guess is that it is a flying insect or grasshoppers. Dusting the plants with sevin is oftentimes an effective control. If this does not work I will need to see a picture ofthe plant and a picture of the gummy mass you are talking about.

John, we have 2 very established dogwood trees that over the past 2 years have begun to start dying… lots of dead limbs and sick looking leaves. Is there a disease specifically involving dogwoods that could cause this . We are certain we will have to cut them was curious as to what might have caused it. I’m very sad… they were beautiful! Linda in Mt. Olive 11. July 2018

Well, a friend of mine, just today said he had to cut two down over the weekend. Dogwoods have several problems but the most common is a dogwood borer which is generally enters the trunk and will kill the tree eventually if not removed. Also there is a petal blight that affects the blossoms and will eventually kill the tree. And finally if they are too wet over a period of time or too dry especially going into winter this can hurt them enough to eventually kill them.

Hi John, mostly dead sweet gum tree just fell in my back yard from adjacent property. Rather than hauling off, might there be benefit of turning the softer, more decomposed portions into useable mulch? Thanks for any suggestions! 25. June 2018

I would haul it off.Sweetgum is not a good tree to grind and use for mulch and if you want to use it for mulch it will need to age before applying.

Hi John, what are some good plants to help absorb water run off and prevent erosion? I live down hill on a slope and our yard gets a lot of water. 22. June 2018

Here are a few in various sizes. All types of Magnolias like moist to wet soil. A great shrub is Clethra and for a great perennial try Siberian iris. Hydrangeas like well drained soil with some degree of moisture. As for a ground cover I think liriope is hard to kill. If you could be more specific of what you want perhaps I could produce a list for you to choose.

I have 2 questions- #1 how to know when to harvest fennel? # 2 when to plant kale, cauliflower, beets and spinach. 6. June 2018

Of course you can use the “leaves” to season things but the general rule is when the fennel bulb gets the size of a tennis ball it is ready for harvest. Probably it will be mid to late summer this year. As for the cauliflower, beets, etc depending on the heat I will plant sometime in September around the 15th when the nights begin to be cooler.

Hi John. Curious if you have experience growing calla lilies outside here in Bham. I have 3- 36″ containers that I treat as small gardens. They are in filtered light and i would like to use some calla lilies in this planing. 23. May 2018

I think they would be fine but I would make sure they get some winter protection to keep the pots from becoming totally frozen- john

Hi John. Thank-you for this wonderful website! I am incorporating as many native plants into my garden as possible, in order to promote biodiversity. However, recent research from doctoral student 15. May 2018

Did not get complete message, please send again- john

Should I cut the old wood shoots now on my hydrangeas? 4. May 2018

I did mine about a week ago as I think the bloom buds are showing and all the alive wood has foliage on it now.

Good morning John, my native azaleas have blend nicely this year. However my photographs from last year so very healthy looking leaves but the leaves this year seem to be wrinkled. Any thoughts? 25. April 2018

Wrinkled and off color, too. In either case, I think fertilization is one key to getting the leaves healthy again. Use a product like 15-0-15 or similar formulation and water in well. Since it is relatively young, 1/3 cup sprinkled around the roots should be enough now, then repeat the application again before a rain in June.

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13 thoughts on “Ask John

  1. Greetings John, My beautiful Peace lillies have an infestation of a scaly type of insect…aphids…I attempted to eradicate them by cleansing the stems and leaves with a damp paper towel and then followed up with a banana peel. As a deterrent, I would break off pieces of the peel and place around the top of the dirt. This seemed to work for a little while, but then I notice some of the leaves begin to grow limp and then turn yellow and I just cut them off. I would appreciate any suggestion and I really prefer the “Natural” remedy, but am open to whatever help you can offer. Thank you.

  2. thank you for replying re: fertilizing my various hydrangea types. I’m going to purchase the 15-0-15 you suggested and I plan to put some, dry, around the base of each plant. Some are very mature–the latest additions were planted in October, 2014. OK to treat all one time either now or very early summer? Thanks again.

  3. I transplanted some daffodils several years ago from my family home in Grove Hill, AL. The blooms do not seem as bright and yellow as they did in their previous environment. Is there a food they need to be more colorful and not so pale yellow? The foliage looks great; only the flowers are not as bright.

    • It might be several things, but usually the depth of color is pretty constant. Once they finish blooming, I would give them a bit of fertilizer. There are products especially for bulbs, but an all-purpose fertilizer like 15-0-15 (which is what most of us need to use in this area) can be sprinkled throughout the foliage. Also, if the bulbs you dug were in a sunny spot, and yours are in shade, that might affect the color somewhat. Other than that, I really do not have any ideas. Let’s hope next year the color will be brighter and clearer.

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