Caring for your Tree Rose is very similar to bush roses
There are special challenges to consider if you want to grow rose standards:
May require more water than bush roses
Must be staked
The standard, or trunk, is susceptible to sunscald
The canes, being elevated, are more exposed to winds and susceptible to dessication
Requires rather elaborate winter protection methods in zones 4 and 5
Selecting your tree rose:
When shopping for your tree rose, remember that the trunk is not only very exposed to sun and wind, but it needs to support the full weight of the rose and be strong enough not to snap in the wind. You will need to stake your standard to prevent breaking, but do try to select a sturdy trunk to start with.
Staking your tree rose:
The trunk of a rose standard should be staked to support the weight of the rose. If you have selected a site exposed to wind, this is very important. High winds without adequate staking can cause the trunk to snap. It may be necessary to use two or three stakes in windy areas.
In warm regions you need to also be concerned with strong sun that dessicating winds. With standards, "sun scald" on canes is a very serious problem. But even if you just tie the support stake on the south side of the can, that will help shade and protect the trunk from sunscald.
Caring for your tree rose:
Follow the care instructions for the variety that is grafted to your standard. Once your tree rose is established, the only difference in care is to remember that your tree rose may feed a bit more heavily that a shrub rose. Most gardeners feel that extra water and fertilizer are used simply because it has further to travel to get to the roses bush. But obviously, the trunk itself is feeding too.
Once planted, spread a thick layer of mulch around the tree rose to prevent splashing water. Water deeply every 4 or 5 days. You do not need to fertilize after planting, the organic amendments you mixed into the soil will feed your rose slowly as it becomes established. I would suggest that you should not need to feed your rose tree until the second season if you have adequately amended your soil with compost and manure when planting. The second season start a regular feeding schedule of organic fertilizer once a month. Chemical fertilizers are not recommended, causing great foliage growth but less blooms. Stop feeding about six weeks before your average first frost date. This will prevent new growth that is easily winter damaged. I confess though that I do continue a light feeding schedule a bit longer in zone 4. I believe it keeps my roses stronger and healthier going into winter. I do, however, try to feed late in the season by top dressing with compost.
Pruning your tree rose:
The most important thing to remember while your tree rose is establishing is that the trunk is not very strong yet and the roots are not well established. A top heavy rose can topple over or snap on a windy day. You should not allow the top graft to become overgrown. You will also want to keep the top growth balanced so the weight is evenly distributed. This will not only make the tree more attractive, but will keep it from slowly tipping. With that said, heavy pruning will keep your rose standard strong and healthy with plenty of blooms.
Pruning a rose tree is almost more simple than pruning rose shrubs or climbers. You will of course remove any dead, diseased or broken canes, as well as canes that cross each other. Completely remove canes that as necessary to maintain a balanced growth, keeping in mind the natural form of the rose. Keep the center of the rose open for good air circulation and to allow room for new growth. Keep the form rounded if you like, or a more natural oval form. Then just shorten all canes to about three or four inches, leaving about one to three bud eyes on each cane. If you leave the canes too long, the rose head will get too big. If you have a grafted weeping rose (ground cover roses) new growth will naturally weep as the canes tend to grow long quickly. Prune your tree rose each year and it will be easiest to maintain the original form. Prune after the last frost in very early spring before growth begins. See rose pruning instructions for more detailed information, but remember that roses are actually pretty tough. Don’t worry too much about pruning wrong or too much.
Special needs of tree rose:
Tree roses are very tender and require careful winter protection in all but the warmest climates. Those grown in containers can be brought indoors when dormant and kept barely watered in a cool space until spring.
There are some things to keep in mind about rose standards grown in containers:
There are limited types of roses suited for container adaptability.
Containers require more frequent feeding and watering.
Plants in containers are more susceptible to overheating and freezing.
Container plants require re-potting as they grow.
They must be moved indoors or winterized.
Containers may experience soil compaction.
Hanging baskets can accommodate smaller roses.
Several methods of protecting tree roses are detailed on the next page.