I have Red Tips that are 12 to 15 feet tall. I would like to trim them down to 6 feet without causing any harm to the shrub. My thought would be to trim down one third of the growth over a two-month time frame to the desired height (which is 6 feet tall). Also, what other type of plants grow well with red tips?
Sounds like you have the pruning part down--this would be an acceptable method for cutting the plant down without harming it. As for companions, nearly anything sharing the same or similar growing requirements, as well as those complementing the shrub's red-colored growth, would be suitable. This is more a personal preference.
My parents have an enormously high row of red-tip photinias that shield their property from a cotton field. They have lost at least one plant over the past few years. The plants lose their leaves and eventually die. My parents are concerned that this will eventually spread through the entire group of plants. What can they use to kill this fungus?
Using a fungicide called Banner Maxx or its generic and cheaper form called Honor Guard should do the trick. There is also a product called Mancozeb that works very well. The Mancozeb will leave a bit of yellowish powdery residue on the foliage which is part of how it works.
We have a rainy climate right now. I keep fallen leaves picked up and the trimmings picked up as well, but I need to do something not to lose the plant to the fungus I just read about. Can you help me? I need the hedge row to keep the neighbor's yard out of mine.
Remove and destroy fallen leaves, prune off diseased twigs. Avoid overhead irrigation. Fungicide sprays (copper-based products) are also generally necessary for this disease, beginning from bud break and applied every ten to fourteen days until all foliage has matured. Mature foliage is no longer susceptible to infection.
What fertilizer do you use on red-tip photinias? I have several that are about 20 inches tall, and I don't think that I used the correct fertilizer.
An even fertilizer (8-8-8 would be fine) would be good. Fertilize once in spring and once in early fall.
When should I prune a 3-year-old red tip photinia?
Prune your Photinia anytime between spring and early fall, with late spring/early summer more acceptable. Red Tips are excellent candidates for rejuvenation pruning. To rejuvenate the plant, cut it all the way back to the ground...to about 6 inches from the ground.
How far apart should I plant red tip photinias apart for privacy?
About 3 1/2 to 4 foot spacing should be sufficient. This article should help as well: https://www.gardeningknowhow.com/ornamental/shrubs/photinia/growing-red-tip-photinia.htm
How deep and wide should a hole be for a 5-gallon Red Tip?
Plant them at the same depth they were growing in the pots. Planting too deep will cause the slow demise of the plants. This article will also help: https://www.gardeningknowhow.com/ornamental/shrubs/photinia/growing-red-tip-photinia.htm