Mar- Apr
You will have blooms 5 to 7 weeks after you prune. Generally, the more petals a rose has, the longer it takes to mature. You will need to apply more fertilizer, because once you start cutting blooms the bushes will immediately start to re-sprout and give you a second flush of bloom. Continue spraying the roses with a fungicide. Check for bugs. You may begin to see aphids. These are little green insects that suck on new buds and new growth. They can be squished with your fingers if there are just a few. Use an insecticidal soap if they are found in large numbers. In April, you may see scarab beetles in the blooms. They can be knocked off into a jar of water with a little Clorox added. (Or they can be squished between petals or rose leaves). April is often dry and sometimes you will get a infestation of spider mites later in the month. They live on the underside of the leaves and are very small. If you have them, the leaf will start to lose color and feel gritty or sandy on the underside. A hard blast of water to the underside of the leaves will control them. This should be repeated several days in a row, or every other day for about 3 days, then once a week until the rains start.
Mar- Apr
You will have blooms 5 to 7 weeks after you prune. Generally, the more petals a rose has, the longer it takes to mature. You will need to apply more fertilizer, because once you start cutting blooms the bushes will immediately start to re-sprout and give you a second flush of bloom. Continue spraying the roses with a fungicide. Check for bugs. You may begin to see aphids. These are little green insects that suck on new buds and new growth. They can be squished with your fingers if there are just a few. Use an insecticidal soap if they are found in large numbers. In April, you may see scarab beetles in the blooms. They can be knocked off into a jar of water with a little Clorox added. (Or they can be squished between petals or rose leaves). April is often dry and sometimes you will get a infestation of spider mites later in the month. They live on the underside of the leaves and are very small. If you have them, the leaf will start to lose color and feel gritty or sandy on the underside. A hard blast of water to the underside of the leaves will control them. This should be repeated several days in a row, or every other day for about 3 days, then once a week until the rains start.
May – June
As the weather starts to warm you will need to be sure the roses are getting plenty of water. Also, this time of year, the Chili Thrips may show up. They are tiny insects that attack stems, leaves and blooms. You will first see their damage on new growth. The new little leaves will look crinkled and have brown spots. Some people have had luck controlling them with the newer types of horticultural oil like Suffoil-X. It must be sprayed early in the morning or late in the day, as it will burn the leaves in hot sunny weather. If you are experiencing a bad infestation you will probably have to use an insecticide such as Conserve. It may be marketed under different names. The active ingredient you should look for is Spinosad. It is somewhat less detrimental to beneficial insects than other insecticides. Keep up with your fungicide spray program. Pull off blackspot-infected leaves whether your spray or not (this should be done year-round).
July – August
During these hot months you need to water regularly if we are not getting rain. Roses in pots will need to be watered daily. Your goal should be to leave as much foliage on the bushes as possible. Cut very short stems when you remove blooms. Expect to see your blooms half the size they were a couple months ago. Fertilizing with a low nitrogen product is recommended by some, so that you do not encourage a lot of new tender growth that will attract bugs. Many rosarians have good luck fertilizing with Milorganite and K-mag in the summer and early fall. Keep spraying (and removing only diseased leaves). Keep an eye out for Chili Thrips and spider mites. Tip: ‘Veteran’s Honor’ puts out pretty nice blooms even in hot weather.
Sept – Oct
Your rose bushes may not be looking too good this time of year and you may be tempted to prune, but it is best to hold off until milder weather arrives in October. Once the extreme summer heat is passed it is okay to do some pruning, although it is best to wait until winter to do hard pruning. (Hard pruning usually means removing up to half the height of the bush and all the foliage). Be sure to fertilize now and you will have some nice blooms in the coming months. Keep up the spray program!
Nov – Dec
Your blooms should start looking nicer now. You can start cutting long stems again. Fertilize, so that you will have nice blooms through Christmas and into the new year. And yes, keep up with the spraying of fungicides unless you have disease-resistant roses.