'Garden Clean Up'
We have just finished with Thanksgiving, and are looking forward to Christmas Day in a very few weeks. Now is the time to start thinking about our garden clean up.
This is one of the most important times in having a clean garden this next spring and summer. By doing a good job now we will element a lot of work through out the coming rose growing year.
Some important supplies we need to obtain to do the job. We will need to have some type of dormant spray, and we need it on hand when we prune our roses. We will also need a pre-emergent to prevent any weeds from coming up in the rose beds if you do not plant companion plants near your roses. We may need to obtain a material to seal the canes when we prune.
The first job we need to do is remove any weeds or other growth from the area where to roses are planted, then pull back the mulch and/or soil from around the bud union. Remove any unwanted mulch from the rose bed and return it to the compost pile, which is still working so the action of composting will get the removed material hot. The heating within the compost should kill many of the over wintering insects and fungal spores.
Check the bud union for any evidence of crown gall or other insect or fungal damage. At this time with a brush or other cleaning instrument clean the entire bud union of old bark and dirt which is covering the bud union. By cleaning the bud union it will promote new basal breaks and renew the rose plant.
You cannot remove the bacteria that causes the crown gall once it has infected the plant, but if the plant is one that you cannot find a replacement for, you can remove the effected gall and treat the area with a strong solution of a fungicide such as bleach. Then allow the air to reach the effected area of the bud union for a few days.
With the rose bed clean of all leaves, unwanted mulch, etc. and the bud union cleaned you are ready to dormant spray your rose beds. This dormant spray should help prevent a lot of problems in the spring, by killing over wintering insects along with some of their eggs, and the fungal spores which cause powdery mildew, black spot and rust. In our climate on the floor of the valley, we very seldom see black spot or rust, if we do it has been imported from the outside. Also, if we can keep the powdery mildew from appearing in April, May or the first part of June we should not have to spray for fungal problems. After the first of July it will normally be too warm for fungal problems.
Dormant spray comes in two common versions, one the oil type and the other the lime/sulfur type. The first works by coating the insects with oil and they die from the lack of air. The second is Lime /Sulfur which was first used in about 1851, and has been used on a number of crops other than roses. This product should not be used when the temperature is greater than 85°.
Both products should be applied to the roses as soon as possible after pruning is completed. If you wait a few days in our climate, the buds will start to swell and could have new foliage in a week or so depending on the temperature. Both these products should be sprayed both on the canes and on to the bud union to the point of run-off. The rose bed should be also sprayed. With the lime/sulfur dormant spray you will get two side effects. First, it would have an effect on the pH of the soil and second, it may effect the soil ability to absorb water.
It must be remembered that the dormant spray has to be applied when the roses are DORMANT!! and on days when the temperature is less than 85°.
If the foliage has started to develop it is too late to dormant spray with the oil or lime/sulfur. If you find you have missed the window of opportunity for those products, then use the insecticides and fungicide that you use during the growing season.
If you have to make a decision on whether to seal the rose canes or spray, do the spraying first then come back to the sealing of the canes. The sealing of the canes prevent only one problem where as the dormant spray can help with many problems. If you can, use the oil spray one day and come back in a few days and apply the lime/sulfur.
To finish up with the clean up and prevention of problems, apply a pre-emergent to the area around the rose where you don't plant companion plants. Myself I feel any thing in the rose bed that is not a rose is a weed, I apply the pre-emergent to the entire bed.
Even though this is winter, we do live in an area where we get very little rainfall so be sure to water your roses when they need it. You can determine this by checking the moisture about a foot from the rose plant at about eight inches deep.
About the first of February you should start feeding the roses.