Photinia rejuvenation

Asked January 16, 2015, 4:59 PM EST

I've communicated with you a couple of times about the issues I've been having with my photinia. In October, you sent me detailed info on the rejuvenation process which I started yesterday. I've decided to go with cutting it all back at one time, but after an hour of careful pruning (cutting at an angle away from the bud, etc.), I had only progressed about 5 to 6 feet. My photinia follows the entire deck and is about 6 feet high and 67 feet in total length. Can I use hedge trimmers to cut the height down to about 4 feet or so and then finish the refining pruning by hand, or should it all be done by hand?

Josephine County Oregon photinia lrk horticulture

23 Responses

Yes you can cut it all down to 4 feet with a hedge pruner and then do the final renewal cuts nearer the ground later or at your own pace, as long as you finish the heavy cuts before the plant starts trying to regrow.

Thanks for the input; it will sure speed up the process!

Hi! I'm back! I cut all (16) photinia plants down to 4 feet with the hedge pruner as we discussed. I've been working on the final renewal cuts (by hand) and they are now down to about 18 inches. I'm really getting a good cardio workout as some of the branches are 4 and 5 inches in diameter!!

I have more questions: Is 18 inches low enough? If not, what's recommended? When cutting the branches, should they be cut at an angle. If so, should the lower end of the angle be facing inward or does it matter?

Thanks again for sharing your knowledge and for your patience.



Cutting at 18 inches high will allow plenty of new shoots to arise. You can cut it lower if the aesthetics is more pleasing to you, but it is not going to have as many shoots if you cut it really low. Don't worry about the angle of the cuts when renovating plants with big cuts, it doesn't matter. I would say when making decisions about where to cut the trunks off. If the trunks are old and rotten you should take them all the way down to the ground. If they are sound, cut them at the height you want.

Glad to hear you say that 18 inches is a good place to stop! Fortunately, all of the trunks are solid; no dead wood at all, so the photinia and I can now take a much needed break. My next questions are about watering and fertilizing. They're on a drip system, so when should I start regular watering? How often and for what duration? Will I need to fertilize in the Spring? If so, what is a recommended product, and how often?

Have a great day!

It sounds like those plants grew pretty well without much care. The more you water the more they grow, so you dictate the vigor through your water and fertilizer. In general those plants don't need more than .75 of an inch of water a week from June through September to look nice. I wouldn't fertilize them very much since the more growth they make the more they are susceptible to leaf spot disease. Give the whole stand 4-5 lbs of a 16-16-16 every other year in spring, and give them 10-15 lbs of lime on the opposite every other year schedule from the triple 16. You will just need to prune more frequently if you water and fertilize more than this.

Steve ~ I just want to thank you once again for your input and patience with my many questions over the past several months. It's been quite an experience and I've really learned a lot. I'll keep you posted on the progress of my rejuvenation project. Juanita

Glad to know I was helpful.

Hi Steve ~ I'm assuming this response follows the thread of our earlier conversations, so I'll get right to it.

I'm pleased (and excited) to report that the Photinia are coming back to life! The plants are progressing at different rates - am I correct to presume this is normal? Of the (16) plants, two have no growth at all, and one has just a single, tiny shoot. They're at different locations in the layout and the trunks/branches are sturdy and alive. The plants on either side of each are looking good, and the drippers are all working. Should I be concerned? Or just be patient? Thanks ~ Juanita

It will be very unlikely if any of the photinia die. Those plants are very tough-hardy so be patient. Keep them moist but not wet. With minimal growth going on the moisture use is limited.

Thanks for the reassurance. I'm now preparing to fertilize with the triple 16 as you suggested, but before I do, I have a couple of questions:

(1) After these photinia were planted (many years ago), the landscapers laid the drip line down, then added red lava rock as a finishing touch leaving just the emitters exposed. Do I need to clear all the rock away from the base of each plant so that the fertilizer can reach the soil?

(2) Also, I'm in a heavily wooded area and have several feeders out for the wild birds. Is there any chance that the birds might be attracted to and/or ingest the fertilizer? Would it be harmful?

Thanks ~

Juanita

If you are only watering with a drip system it is more difficult to get the fertilizer into a solution to soak into the soil. The only way you will get this fertilizer into a solution if you broadcast the triple 16 is to get some good rain. I use a 5 gallon pail to premix fertilizer in water then I pour the solution into the root zone. You can just drop some granular fertilizer near the drip emitters but that wont saturate much of the root zone.
The granular fertilizer wont hurt birds if it falls into the lava rock or is dissolved into water. I have never heard of birds harming themselves by eating fertilizer.

Since I can't depend on the rain, I'll go with premixing the fertilizer in the 5 gallon pail. How much fertilizer to 5 gallons of water?

Dissolve two cups of triple 16 in the 5 gallon bucket. Then pour it out over a 3-4 foot stretch of the plants.

The triple 16 fertilizer that I have is granular. Will it dissolve in water or is there a concentrated form I should buy?

The triple 16 will dissolve in water, but it takes some time. It is ok to buy something like Miracle Grow that dissolves faster, but look for a blend that is not mostly nitrogen. Get a balanced fertilizer with all three NPK.

Re the fertilizer, -it's nice to know I have choices.

Thanks again for all of your great advice and input.

Have a great Memorial Day weekend!

Juanita

Hi Steve ~ It's been (2) months since I last contacted you about my Photinia project and, for the most part, the recovery/growth process has been quite positive. Most of them have vigorous growth, some already up to three feet tall - and wide. The growth varies from plant to plant, which I presume is related to the different amounts of sun exposure they receive. However, there are (4) plants I asked you about in May that I'm still really concerned about. About a month ago, they all finally started showing signs of life, but have since stalled. One of them put out a couple tiny shoots but they soon turned brown and died. The shoots on two others have developed into leaves, but there are only 5-6 of them, and aren't showing much growth, and the last one only put out 2 shoots. None of them are near each other and the plants on either side quite healthy. Any ideas? Is there still hope?

I also have a couple questions about pests and treatment. About a six weeks ago, I had an invasion of aphids which I treated successfully with Safer insecticidal soap. At the same time, I noticed that all of the plants had multiple leaves which looked like they had been nibbled on. I was thinking earwigs, but never saw any, and the problem went away at the same time I was treating for aphids. However, in the last couple days, I've been finding earwigs hiding in the fold of brand new leaves! Arrgh! Is the Safer an effective product for earwigs or is there a better one?

Lastly, I thought there might be a connection between the aphids and the stunted growth on the (4) plants mentioned, but looking back on my garden notes, the aphid invasion occurred a few weeks prior to the plants having any signs of life.


Thank you for your time ~

Juanita

Sounds like a few plants were weak and are not going to make it. If they dont make new growth this summer they probably never will. You may have to dig them up and replace them. They must not have been healthy when you pruned everything.
The photinia can take earwig or other insect eating without significant damage, it is just cosmetic damage. If you want to spray them use Spinosad. It is a good general insecticide that is not super toxic to people. Safers will not kill earwigs.

Hi Steve ~ I took your advice and in October, replaced the (4) Photinia that looked pretty puny at the end of summer. I also replaced the drip line and emitters which were over 20 years old. Both the older and the new plants made it through winter and all look pretty healthy. When I wrote to you in July, I noted that the (11) older Photinia were all showing vigorous growth and were about 3 feet high and wide. Fast forward to now, and several of them are over 5 feet high (and wide), but are kind of gangly looking.

I know that now is the time to start pruning, and would like your input on how to do it. My goal is to have each plant fill out as uniformly as possible, and eventually merge to become a hedge as they were originally. How far back should I prune the branches that are growing every which way? Once I've decided where I'm going to make my cut, do I make it above or below an existing leaf?

I'm also seeing some black spot and leaf curl on the new growth that has emerged over the last couple months. What's causing that, and what can I do about it?

Thanks

Juanita


Now that the photinia have started to make good growth you have to decide how tight a hedge you want. If you want a very tight hedge you should cut the new growth back to just a few inches above the last cuts. If you want the hedge to be a little more open without a cropped look, then just tip the vigorous shoots back by about a foot. It is up to you how severe to cut the new shoots. The hedge will regrow either way. When making a cut, do it above a leaf petiole or bud.

The black spot on photinia is a fungus and you will need to spray a fungicide when the new growth comes out in spring. That will protect the new leaves during the rainy period before summer.

Steve ~ Thanks for the pruning tips. I also have a couple questions:

(1) Regarding the leaf spot: what (brand) fungicide do you recommend?
(2) Regarding fertilizing: You mentioned alternating the triple16 (which I did last year) with lime. How much lime would I need for 15 plants and what's the best method of application? To refresh your memory, my plants are on a drip line and are also surrounded with red lava rock.




You can use either Daconil or Immunox. Either work well.

The lime I buy only comes in 40-50 lb bags. I use prilled lime which is easy to handle and can be spread by hand or with a whirly bird spreader. Use about 2 cups per plant. You can ask the DC Coop or Coastal if they have smaller containers to sell.