Month by Month Tasks for Rose Growing in Utah
This is called the “windy month”, but the latter part is usually our best planting time for bareroot bushes. Depending on the weather, this may also be a good time to begin pruning. Pruning stimulates growth and this should be delayed until the danger of a hard frost is past. Since the weather can be unpredictable in most of Utah the timing of pruning is variable.
Weather permitting, April is usually the best month for pruning. Prune before the leaf buds on your plant have swollen and erupted, but are not longer than an inch or so. If you wait too long to prune after this, you will really be pruning off a lot of new growth, which will set the vitality of your plant to the degree the new growth gets removed. For those planning on exhibiting in the June rose show, prune 8 weeks before the show. Look over the bushes, cut out any deadwood, crossing canes and those smaller than a lead pencil. Seal all pruning cuts with Elmer’s Glue. Look for an outward facing bud and cut at a 45 degree angle ¼ “above the bud or bud eye. Prune for an open center and leave 3-5 canes. Prune high or low, to make the bush do what you want. Prune to 6-10” for large but fewer blossoms. For more but smaller blooms, prune the canes to 18” in height.
FERTILIZING: Apply the first fertilizer when the leaves have started to grow. Water your roses well before fertilizing if the soil is dry. Now is the time to put on alfalfa meal (which contains root growth hormones) one or two cups per plant, and Epsom salts (magnesium sulfate), ¼ to ½ cup per plant. Epsom salts promote the eruption of new basal canes, which is a good thing. Any granular fertilizer can now be applied with about a handful or so sprinkled on the surface around the plant in about an 18 inch dimeter circle. The NPK ratio should ideally be about 1:2:1, but 1:1:1 will work fine. To know if your fertilizer ratio is correct for your roses, you may send a soil sample from your garden to the Utah State University extension office. This test will tell the mineral content of your soil.* LAWN FERTILIZERS WILL NOT WORK as they have a ratio of about 20:0:0 (very little phosphorous or potassium). Once the leaves have fully developed, it is time to start foliar feeding if you want the biggest and most colorful blooms. Start when the leaves are well formed and continue every 2-3 weeks until July 1st or so when the extremely hot weather kicks in and the roses go slightly dormant.
*For details on submitting a soil sample, go to the following website: usual.usu.edu
Now is a good time to plant your roses purchased in containers. Good bareroot stock may still be planted, but hopefully planting should be over. Fertilize newly planted container roses with a liquid fertilizer ONLY for the first season. You may prune a second time to eliminate unhealthy canes. Use the Integrated Pest Management (IPM) approach to control pests and diseases. Consult a Consulting Rosarian if you need assistance. Give water as needed. Rose shows will be upcoming so be sure to disbud early on hybrid teas, and perhaps grandifloras, to be shown as single specimens.
The IPM (Integrated Pest Management) approach to pest control combines cultural, physical, biological and chemical tools to minimize the economic, environmental and health risks involved. Monitor the pests that you have in your rose garden, take preventive cultural measures. Further, to establish acceptable levels, add physical, biological and/or chemical controls if needed. Use these steps on an individual basis with each garden pest until you reach the level of control that you are comfortable with.
Normally, June is Rose Show month, but this year it is not. The American Rose Society National Convention was postponed until August 17th to 21st in Colorado Springs and the Utah Rose Show has been postponed to September 19th in Salt Lake City. Things are very different this year because of the Corona Virus pandemic but during this month the roses will still be out in all their glory, in public and private gardens and on the street edges as you pass by. In a typical climate year the big “Spring Flush” as it is called should be from the first to the middle of the month. When the bloom is on, fertilizer should be applied for the second time. The first fertilizer was applied in April right after the plants started to leaf out. Roses cannot take up materials until the pumping power is there in the leaves, so don’t ever forget about deep watering. The hot days are beginning and evaporation is starting to get high.
Deadheading, or the removal of dead blooms, is essential or your roses will form hips (seed pods) and stop producing new growth as much. Deadheading is a matter of taste as you are trying to keep the bush blooming but you are also trying to keep it at the ideal size for your garden. The less you cut off the more blooms you will get but they will be smaller; the more you cut off the fewer blooms you will get but they will be larger.
This is the beginning of hot weather so water is EXTREMELY important. Continue with IPM (Integrated Pest Management) practices and spray for insects or diseases if necessary. Make sure to keep taking off dead blooms. Apply the next major fertilizing around the 15th of the month. Every six weeks is a good rule, depending on the variety and its needs.
Prune your once-blooming roses now. If you prune in the spring you will have few to no blooms because you have pruned off much of the wood that contains this year’s blooms. Most once-blooming roses bloom only from growth on branches that are from last season. After the bloom is over is the perfect time to prune, because the rose will have the entire rest of the season to form the canes that will have next year’s flowers
More heat, so good mulch will help keep the roots cool and save on the water bill. Apply the last application of fertilizer around the 15th to 31st of August. Mildew will probably be the greatest problem this month, so have your plans formulated to deal with it.
The last of September and the first of October is what is referred to as the “Fall Flush”. This is normally the second best time of year due to the cooler weather. The blooms last far longer on the bush, so there will be more blooms going at the same time. No more fertilizer on the roses is needed but water is still important. Leave the last bloom on the bushes, as this helps to harden them off for the winter. An application of Treble Superphosphate will help get the roses into cold weather.
This month should end the blooming month for roses. Get beds ready for the spring arrival of new roses. If we have an Indian Summer make sure to keep your roses watered to avoid damage that may not show up until next year. In late October if the cold weather comes and the ground is frozen over, hill up the bushes. You may use leaves (oak are best), compost, straw, or soil pep. Soil may be used but it must be brought in from another area of the garden. This will help keep the bushes cold. Warning, this must not be done too early, the ground must be frozen.
Rose beds should be frozen by this time, if not hilled up in October you may do so now. Extra-long canes can be shortened at this time to prevent whipping in the winter winds, which could loosen the roots. If you have trouble with broken canes because of heavy winter snowfall, bushes may be tied with twine to prevent breakage.
Give garden nursery gift cards as Christmas gifts. Winter evenings would be a good time to bring tools in, clean them, oil then, and sharpen, so they will be ready when there is work to do. When snow comes, heap it on the rose bushes. If there is no snow, water your roses once a month.
Weather may change any calendar. In this mountainous country, Nature is a changeable lady so work accordingly. Utah has a diverse climate that ranges from hardiness zone 3 to zone 7, so be sure to check the hardiness zone where you live and purchase roses that correspond to your area. In the southern part of the state, around St. George, roses bloom about two to three months before the rest of the state. In the high mountain locations the growing season is shortened greatly so purchase roses that do well in colder weather.