When to prune and fertilize rose bushes

In southern California winter is usually short and sometimes confusing. Winter for some plant life is a time of withdrawal that precedes renewal. For roses, it is necessary to help them in that process. Now is the time to perform a few procedures to help reset the hormonal clock and get them ready for a great year of rose blooms. That's the main purpose for pruning.

According to all accounts and experienced rosarians, the proper time is "late winter." This phrase has many meanings in an area like Southern California which has numerous weather zones. The important thing is gardeners want to prune late enough to avoid risking frost damage to the tender growth that will emerge as a result of pruning. In most of the region, the last average frost date is mid-March, so that means gardeners are probably safe pruning in mid to late February. It is always a gamble, and the best advice is to watch the weather. If there is winter rain during January or February, pruning can be held off awhile since these rains are cold making the ground colder and wetter than usual. This year the weather hasn't been severe enough to actually prevent new growth. I have observed that pruned or not, new growth is appearing and buds forming very short canes. Different parts of a yard may have other conditions effecting gardening. A south facing wall backing the plants will be warmer than a shadier area. Soil composition will have differing effects. A generous layer of remaining mulch will improve soil conditions.

If you haven't began or finished pruning, don't fear. There is still plenty of time to have blooms for rose shows or special spring events. The recent rainy periods and warmer-than-usual weather which has created a great environment for fungi diseases; examine the roses and, if any rust is found, remove all the leaves from the plant at once and discard into green waste bin. I do this step anyway on every bush before pruning because it helps me see the structure clearly.

As I said before, the major late-winter pruning reset the plants' hormonal clock. A wake-up call to begin a new life cycle–like restarting a factory. After this pruning, gardeners can usually expect a flush of blooms 8 to 12 weeks later, depending on the temperatures during that period – the warmer it is, the shorter the time to blooms. But all things being equal, if they prune in the latter half of February, they will likely have blooms for 2020 rose shows scheduled in mid- to late-April. If a gardener would like blooms for a specific date, count backward approximately 10 weeks from that date. Pruning should be complete on this date.

The following procedures mostly apply to hybrid teas and floribundas, but are reasonably serviceable for minis. They are not really applicable to climbers, ground cover roses, trailers or shrub roses – all those types have their own pruning methods.

Before pruning, be sure to have good pruning tools and gloves with arm protectors, long handle loppers and sharp clean "bypass" hand pruners. What does "bypass" mean? Take a look at the pruners: Bypass pruners have a sharp cutting blade, which slices through the cane, and a dull curved non-cutting blade, which holds the cane in place during the cut. The sharp blade "bypasses" or over shoots the dull curved blade. It's a good idea to have a range of pruner sizes handy. Each size has a limit to the diameter thickness for which it is most efficiently used; using too small a pruner on too large a cane can damage both. At minimum, have a pair of loppers and a standard-sized pair of hand pruners that fit comfortably in your hand. A saw can be handy if you have some older plants with large canes that may need to be removed.

All tools should be kept clean, sharp and in good repair. Rubbing alcohol is ideal for cleaning cutting blades, before and during the job. It also helps prevent transmitting diseases from plant to plant, and you can use it as first aid for punctures and scratches to the skin. A good pair of leather gloves are necessary with long sleeves or separate pair of sleeves to protect the arms.

Before starting the job, lubricate the moving parts with a little light oil, such as 3-in-1 oil, and make sure they operate without resistance. Sharpen each blade with a small diamond file, which are available at garden centers, trying as much as possible to match the original bevel of the blade. Every 100 cuts or so, swipe the file over the blade a few times to keep it sharp. If a gardener notices that the pruners are crushing the stems and/or leaving a tail, it's past time to sharpen. To minimize damage to the cane, keep this rule in mind: The sharp blade should always face the part that will be left. This position will minimize the crushing of the cane or stem as it will be the part that is discarded. This rule also works for preparing stems for arranging or putting into a vase.

Now, decide what style of pruning feels comfortable. Buds are found in the "axil" where a leaf meets the cane; leaves spiral around the cane at about 1.5- inches intervals. This position places outward-facing buds about 4-inches apart. If a gardener prunes lightly to moderately, and if frost damages the tender young growth, then they can still re-prune to the next bud down.

See Photo 1

In Southern California, rose bushes can grow quite large, so start with some gross pruning to bring the project down to size. I use loppers to cut every bush down to about 3 feet high. This size lets a gardener examine the structure of the bush, and to use their hand pruners to more easily remove canes that are twiggy, dead, crossing other canes or passing through the center of the plant. Also remove old leaves along the way so the structure of the plant is easily seen. After removing all that stuff from the interior of the bush, do the final pruning. Attempt to leave a domed top to the degree possible so the plant will bush out in a pleasing, balanced manner.

A gardener will make two kinds of cuts. Some cuts remove an entire branch; make these flush with the surface of the parent cane. Other cuts simply shorten a cane. It is important to position your pruners to minimize damage to the plant. Position the pruners so the noncutting blade is in contact with the portion of the cane that will be removed, and the cutting blade is on the side of the cut that will remain on the plant. (See Figure 2.) This will make more sense when you a gardener is actually holding the pruners and getting ready to cut. Also, always prune above an outward facing bud with an angled cut. (See Figure 3).

See Photo 2

See Photo 3

For shrub roses, cut them back to conform to the space they are meant to fill, inspect and clean out dead and diseased material from the center, shorten canes and remove about one-third of the growth.

A word of caution when pruning: Look for the small nests of hummingbirds, as this time of year is the nesting period for two varieties in our area. Also, if a gardeners discovers praying mantis egg cases on any branches they remove, find a place to put them where they will be undisturbed and hatch out so the garden can benefit from the offspring.

Clean the ground thoroughly of all rose debris and dispose of all cuttings and other materials in the green waste bin and put it on the street: Do not compost it. Apply a dormant spray to the plants and the soil surface to ward off diseases. Then apply 2-4 inches of composted mulch to cover the entire garden area.

The first fertilizing time will be when new growth is about 2 inches long. I recommend lower values of the three elements (Nitrogen [3], Phosphate [4],K Potassium [3]) with slightly higher value for Phosphate. In two weeks begin with heavier feeding every two weeks for great blooms or at least monthly. Now would be the best time to assess the irrigation system for any needed repairs while there is no new growth and mulch has not been spread.

Be sure to visit Rose Haven Heritage Garden, 30592 Jedediah Smith Road in Temecula. The cross street is Cabrillo Avenue. For more information, visit http://www.TemeculaValleyRoseSociety.org.

Spread the word and spread the joy of roses.