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.

If you need to include a photo, you can email your question to BirminghamGardeningToday@gmail.com


Sun loving ground cover 14. June 2016

I could use some more details. Dense is Asian Jasmine and it hugs the ground, and once established it can be maintained with nylon-string trimmers. Almost all of the Junipers like full sun, and you can get them in a variety of sizes (heights). Many folks use these on slopes. Others include winter Jasmine, some of the new rose types that trail, prostrate loropetalum (Chinese Fringe),etc. A good description of the space you are considering, and the quality of the soil would help me be more specific.


John, can we grow Muhly Grass in Birmingham successfully? 9. June 2016

It certainly can be cut back with a string trimmer, but using a mower if the crown is high will probably damage or kill the plant.


What are the times during the year to fertilize Encore Azaleas? I have heard spring , summer, and fall…what are your thoughts? 5. June 2016

I think they should be fertilized each time they finish blooming. So, depending on the type you have, that would be two or three times a year.


The slugs are eating up my caladiums. I’ve used the granules in my flower garden, but I’m still finding big holes in the lraves. What can I do? 2. June 2016

Slug bait usually controls them, but if not I have had good luck pouring beer in shallow tops and putting them under the leaves, and it does the trick over time. But if you have a large infestation, you are going to have to refill the tops several times.


What do you think about products with Spinosad for controlling thripes on roses? 28. May 2016

While I have never used this product, I checked with the Hanna Center at the Botanical Gardens, and they say it is an excellent product. Two things to remember, it lasts only a max of ten days and spraying open blooms can cause burn to the petals.


I love Zinnias and plant them from seed… They always have pretty blooms, but the leaves look horrible! Dry, brown and very unsightly. IS this fungus? how can it be controlled so the plant looks good all summer. Linda in Mt. Olive 24. May 2016

I checked with my friends with the Hanna Center and they agree that if it is just brittle or brown leaves, it is one of two things: the plants got dry and the lower leaves are where the damage is exhibited, or it is just a characterisitc of the plants, as many of the older types have this as a common characteristic.


When should hydrangeas be fertilized? 20. May 2016

See answer below.


When is the best time to fertilize hydrangeas ..we are located in Mt. Olive 35117..Or do they need fertilizer? I have already added some of the ph changer granules to help them turn blue… 20. May 2016

I like to fertilize them when they finish blooming, but some folks think if you fertilize them once flower buds appear, it will increase bloom size. But I always like to do it after flowering, and make sure they have plenty of water when they are fertliized


Do you know of any place local in or near birmingham that carries Joseph’s climbing roses? 17. May 2016

Try “Petals from the Past” in Jemison. If anybody has it they do as old fashion roses is one of their specialties.


In your “how to fertilize tomatoes” you mention scratching in 15-0-15. In other articles you recommend the same 15-0-15 as good general fertilizer for gardens. When I look this up it seems this is what’s recommended for lawns. Also I have not found it in my area, Trussville thanks 10. May 2016

In our area, and especially in Trussville, our soils are high in phosphorus. That is why Auburn recommends 15-0-15, and yes it can be used as a turf fertilizer too (as most fertilizers can). I got a bag a couple of weeks ago at Universal Pro (formally Universal Seed and Supply).


Should I feed my peonies after they bloom? What about other perennial? Thank you. 10. May 2016

Actually, I like to fertilize mine before they come into bloom because of the energy the plants need to bloom. Once blooming is finshed a few weeks, I feed them again to encourage additional tuber growth. Fertilization prior to, and after bloom is a common way to handle most perennials.


For our area, how ofter should I turn my irrigation system on and how long should each station be on if there has been no rain? Thank you! 10. May 2016

In order to save water this time of the year, I irrigate if we have not had rain in 4 to 5 days. As the weather moves in hot of course you may need to irrigate every three days. Currently I have mine on 20 minutes per station, but when summer comes I put mine on 30 minutes a station. While I have an automatic system, when we have heavy rains I turn mine off to save water, then turn it back on when it is dry enough to water again.


Can Kimberly ferns tolerate heat? 12. April 2016

Absolutely, just remember it likes shade and water. Actually, if kept watered, the hotter the better.


I’m the Mt. Olive weed yard….thank for your advise ! Another question in regard to the weeds…I have a nice rock bed around a large crepe myrtle …several years ago I planted vinca (perennial ) and it was beautiful…now there are many many weeds mixed in..is there any weed killer that could be used that wouldn’t kill the vinca also, or should I just start completely over? I have tried hand weeding, but it’s futile! Thanks …LD in Mt. Olive 1. April 2016

Well, let me give you a tentative yes, but if you could send me a picture, I could be more specific. If it is annual spring weeds, you could apply a pre-emergent in the fall and control many of them, and reduce what has to be hand pulled. If it is grass, vines, and woody types of weeds, you can paint them with Roundup on a sunny warm day being careful not to get any of the Roundup on the Vinca. I do this by using a sponge brush dipped into the concentrated Roundup. Be sure and wear gloves and do not splatter. Remember the results are not instant but will take a few day to start dying.


I have a large yard in Mount Olive, 35117. We have a lot of shady areas along with the areas that receive full sun. We have centipede , Bermuda, and a few areas of Zoysia grass , but mostly weeds! Every type imaginable. What would you recommend as a week killer method to try to kill and keep all the weeds ar bay? 29. March 2016

Mixed types of turf and large yards are tough to handle. First and foremost, cut the weeds and turf lower than usual now, and keep it cut until the good grass starts turning green. I would recommend you use a pre-emergent herbicide for mixed turf types on an area that large, instead of spraying. I would go to your local farm supply or feed and seed store, tell they the type of turf you have, and ask for a herbicide that would control summer weeds and not hurt the grass. Apply when the grass, not the weeds, greens up. Apply at the recommended rate shown on the bag, and they can help you with this. Again in September go and ask for what they have that will control Poa annua and other winter weeds, and apply in early October at the recommended rate on the bag. By doing this year after year, and good grass cutting and fertilization practices, you should be able to maintain a nice looking lawn, but it is going to take time to get the weeds under control.


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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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