Recent temperatures have been quite erratic with periods of warm to very warm days and very cool to cold nights which will influence how quickly the new foliage grows. The warm daytime temperatures will stimulate greater root growth. Truthfully, I think the roses are as confused as we are. Some folks pruned as early as December, I hope the new growth was not frost-damaged on those roses – it’s a risk one takes every year when deciding when to prune.
After pruning roses last month (which hopefully everyone has), you should see new coppery-red foliage that is about two- to three-inches long within six to eight weeks. There has been some cold rain which continues to keep ground temperatures low thus discouraging new growth.
Whether or not your roses have sprouted, apply lime sulfur dormant spray now in order to prevent disease fungi on surface debris from spreading to new growth. Follow the directions on the label. In a new rose garden, or with newly pruned roses that haven’t sprouted, thoroughly wet all canes and the surrounding soil after removing all debris. For roses that have sprouted, be more careful in your application and, be sure to follow the “growing season instructions” on the label.
The time to begin a feeding regimen is when new growth is 2- to 3-inches long. To give roots a boost at the start of the season, sprinkle superphosphate (available at home stores and nurseries) on the soil surface at a rate of one lb for every 10 square feet. Lightly water it into the soil. Also sprinkle one-half to one cup of Epson Salts widely around the base of each plant. (Use half as much for minis and mini-floras.) There is some indication this helps in producing new cane growth.
This is also time to inspect and repair irrigation systems. Drip systems are the most thrifty, and they avoid the problems of above-ground sprayers and sprinklers which waste water and can foster molds (mildew and rust). To answer the question of how much water a rose may need is another of those “it depends.” Much depends on a lot of factors; weather, the size of the plant, the composition of the soil, the cycle of growth, the variety of the plant, and probably several other factors.
Typically a mature, full-size hybrid tea in Southern California soil requires six to nine gallons of water a week when the high temperatures are in the 70s. As temperatures rise into the 80s the rose will require about nine gallons of water per week. In the 90s, the rose will require about 12 gallons per week and even more. A miniature rose, depending on size, requires about one-third to one-half as much. These figures are rough and based on the amount of water needed to maintain the highest level of show quality; the rose will stay alive on considerably less.
Top the rose bed with two to four inches of organic composted mulch.
I use and emphatically recommend organic types of fertilizer, as vs. inorganic or “chemical” ones, because organics are less concentrated (thus less likely to burn), and their nutrients are released more slowly. As your soil develops, you’ll be able to use less and less product and save money in the process.
Our area has had some rains, so fertilizing now is opportune. If you can’t feed now, while the soil is moist and the plants are well hydrated, be sure to water them the day before you do begin fertilizing. Never feed a dry plant! A typical feeding program involves applying products every two to four weeks.