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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Hi John- I have a mass of Endless Summer hydrangeas and a border along my back fence of Limelights. When should I prune those back and how aggressively should I prune? Also when do you recommend planting daffodil and tulips bulbs–once we’ve had a good freeze? Thanks. 16. October 2018

Endless Summer should be pruned immediately after flower if you want to have flowers next year as they bloom on old wood. In the case of limelight the time to prune is in the late winter as these produce flowers on new growth.. As for daffodils and tulips you can purchase them now and refrigerate them until planting. I have waited as long as the first week of January but for me anytime after Thanksgiving is good for the metro area.

Hi John, I need to move some lenten rose, and am not sure the best time to move it. I know one moves evergreens when they are dormant, but with Lenten Roses blooming in mid-late winter, I wasn’t sure if that rule applied. Thanks, Mark 13. October 2018

If you move them this winter say late December or early Jauuary you might not miss their late winter blooms. At transplanting I would remove all the old or ugly leaves. It is one of my favorites

Hi John, I just stumbled across your blog and I have been transfixed for two hours! My question: I have planted eleagnus along my side and back property lines for screening. I want them to be tall, bushy, and grow ‘together.’ I have gotten mixed answers about how to prune the canes. (e.g. 1) prune them all the way from where they emerge from a limb; 2) prune them to about a foot lower than the desired eventual desired size, etc) Please advise! Thanks; Mark in Crestwood 8. October 2018

There are several answers to your question. If the plants are the size you want them then remove the long new shoots at the point of origin on the plant. If the plants are still not the size you desire you have two options this time of the year. You can cut these shoots off(at the point they sprouted from another limb) or you can leave them alone and this will help the eleagnus continue to enlarge in size. Even if you want the plant to get bigger I like to remove the late summer and early fall shoots that appear where the plant will look better in winter and allow the spring shoots to give me more size. So as you can see it depends on what you want the plant to do but one thing is for sure you can count them to shoot up new stems every year.

Hi John! I have 9 “Green Giants” cypress trees, well established, planted in December, 2011. Approximately a month ago, I noticed one on the end color changing from dark green to light green. I checked for dark spots and tried to prune. Now it is a solid brown. Do you have suggestions as to what happened? 5. October 2018

I wish that was unusual but it happens so much especially when we have a wet period followed by a dry period. This is especially true with trees that have grown well for years and seem to be the perfect tree. I have seen this over and over all across the metro area and in fact the same thing happened in my yard. Excellent replacements include Mary Neil hollies and Nellie R. Stevens hollies but there is not a match tree to your cypress trees that I can guarantee will not have the same problem

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.

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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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