March 2010 Consulting Rosarian Report

By: James Armstrong

As I write this (March 8^th), it has been a wild winter with lots of rain and chilly weather, followed by multiple warm spells that made every rose in my garden start to leaf out like crazy. Your roses should also be leafed out by now, and if so, cease all but the very lightest pruning and all transplanting.  Right after a bush has leafed out is the WORST time of year for those activities.  Wait until the foggy day of June or July if you have bushes you didn’t get around to doing last winter. Since I am still not finished with my pruning, the climbers and rugosas are on their own this year, and the remaining bushes will only get the very worst of the twiggy stuff removed.  Now is the time to commence the three “biggie” basics of growing season rose care, WATERING, FERTILIZING and INSECT/DISEASE CONTROL.  Performing these tasks on a regular basis from now till October will assure you of lots of blooms and healthy bushes all year. I water at least once a week, try fertilize every month or two (always follow the instruction on the package), and attempt to spray every two weeks.  I know that most of you already know these things, but everyone should review the basics occasionally.  

WATERING:

Regular watering is by far the single most important element of rose care.  In a normal year, I deep water my cool, coastal, “clay soil” garden once a week and my container roses once to twice a week.  But if you live in a warmer area, or if you have very sandy soil (and that is exactly what kind most of you who live in San Francisco have), you may need to water far more frequently.  Roses in containers almost always need to be watered more frequently than roses growing in the ground.  During a real heat wave, container roses may need to be watered almost every day.  A general rule of thumb from around the country is that roses need an inch of water a week.

During March, watch the rain totals for your area, (buy a rain gage, they’re cheap!!) if you didn’t get an inch or so the previous week, you might need to water.  Use a water meter (also cheap!!) to check the moisture content five or six inches below the surface, and if it registers in the lower portion of “Moist” or lower, go ahead and water.  By the beginning of April, you can count on needing to water until the rains start up again in October.

FERTILIZING:

Fertilizing should commence at the beginning of March and end no later than early to mid-September.  Most rosarians develop their own opinions about fertilizing (strength and frequency, organic vs. inorganic, slow release or regular), and so long as you’re satisfied with your roses’ performance, keep doing whatever you’re doing, and don’t worry about what anyone else (including me!) does.  But, if you read or hear of some new program that sounds exciting to you, don’t be afraid to give it a try.  Roses are very forgiving plants, and if the new program doesn’t do the trick, go back to the old.  The only “hard” rules are: (a) don’t exceed the amount specified on the container; (b) water the day before, any plants that register less than mid “Moist” on a water meter; (c) always water again after applying dry fertilizer; and (d) don’t fertilize new/young plants until after their first bloom cycle.  I try to fertilize every three to four weeks, but at times only manage it three or four times a year.  I usually alternate between organic and inorganic fertilizers.  I like alfalfa pellets, Miracle Grow 15-30-15, fish emulsion, Ace “all purpose” 16-16-16 and anything interesting that’s on sale.

To get my bushes off to a good start, as close to March 1 as possible I will water and then apply Ace “all purpose” 16-16-16 according to the label instructions, and then water again.  As soon as possible thereafter, I will scatter 2-4 cups (depending on the size of the bush) of alfalfa pellets around each bush, and water well.  Always check the label to make sure the alfalfa pellets you buy do not contain molasses (like rabbit food) since that will attract ants.  Any feed store should carry large 60-pound bags (I go to one on Main St. in Half Moon Bay), and I use 4 or 5 bags to fertilize my 200 roses.  The 16-16-16 will start to work very quickly and will be enough to supply the bush with all nutrients for a month or so.  As with most organic fertilizers, the alfalfa pellets must be broken down by the microorganisms in the soil for a month or so before the rose roots can start to absorb the nutrients, and will continue to break down for a substantial period of time thereafter.  So if I work really hard for one day and get both the 16-16-16 and alfalfa pellets around each bush, I do not need to fertilize again for two to three months!  I will try to apply other fertilizers during the growing season, and by adding Miracle Grow to my fungicide spray at the rate of one tablespoon per gallon of total spray mixture, I apply a little additional fertilizer as a foliar feeding every two weeks.

SPRAYING:

Disease/insect control is one of the biggest challenges a rosarian faces, and whether or not to spray is a personal decision.  With 200 bushes, spraying works better for me than any other method I’ve tried.  I (try) to spray fungicide every two weeks commencing in mid-March and continuing till mid-October, and I only add insecticide or a miticide to the mix when insect damage is too bad to be ignored.  However, it may be necessary to spray more frequently (e.g. every 7-10 days) if a bad disease or insect outbreak occurs. 

In general, always water thoroughly the day before spraying, always follow the label instructions, never use more than the label recommends and use the least toxic products that work for you.  Never mix up more spray material than you will use in one spraying since the mixed spray cannot be kept and used another time.  If spray is left in the sprayer after all roses are sprayed, spray it onto the ground in between the roses or on your lawn until it is all used.  ALWAYS WEAR CHEMICAL RESISTANT GLOVES while mixing, spraying and cleaning up.  Wear a long sleeve shirt, long pants, a hat, glasses or goggles and (optional) a mask.  Wash your spray clothing separate from your normal wash, use hot water, detergent, a high water level, and an extra rinse.  Take a shower before you eat, drink, or smoke anything.

In the past I have used a number of different fungicide products such as Funginex, Lime Sulfur, Immunox, Daconil, Baking Soda, horticultural oil and Copper based sprays, often combined with each other (but trust me, don’t mix Lime Sulfur and Daconil) or with insecticides and/or water soluble fertilizers (eg. Miracle Grow).  However, I have given up my exotic blends (the more products you combine the greater your chances of burning the tips of your leaves) and I now use Neem oil every time I spray.  It is derived from the neem tree in India , is very low on the toxicity scale, and is both a fungicide and insecticide.  I will occasionally combine it with another fungicide for serious out breaks, but since it is an oil, I would not mix it with any other horticultural oil.  Neem does a fairly decent job controlling insects and mites as well.  I add other insecticides such as Orthene or Isotox 4 only for very serious insect problems.  However, do not mix Neem and Insecticidal Soap together, since soap and oil do not mix--they break each other down.  Almost all garden centers and “big box” garden stores carry Neem Oil, but the word “Neem” may not be part of the name of the product.  Check the “active ingredients” list on the label and if it states “Clarified Hydrophobic Extract of Neem Oil” that is what you want.  I have heard that people living in the warmer spots of the Bay Area have experienced “leaf burn” when using Neem, but I have not had that problem in cool Pacifica .  But, to be on the safe side, I’d recommend against spraying Neem on a hot day.

I strongly recommend using a “Pump” type sprayer.  Measure out the full amount of water that you will need.  (Plastic milk jugs work well, and I mix up and use at least 2 gallons every time I spray.)  Use water as hot as it will come out of the tap.  Pour ¼ of the hot water into the sprayer.  Pour some of the remaining hot water into a glass jar, measure in the first ingredient (Miracle Grow for example), mix well, pour into the sprayer and mix again.  Continue mixing each ingredient, one at a time (for example mix up the Miracle Grow, and after adding that to the sprayer, mix up the Neem Oil and add it to the sprayer), with more hot water and pour each mixed ingredient into the sprayer and mix everything in the sprayer again after each ingredient is added.  After all products are in the sprayer, add any remaining hot water, mix again, and place the top on the sprayer and screw on tightly.  Shake the contents thoroughly and then pump up sprayer according to the manufacturer’s instructions. 

Set the spray for the finest (lowest) setting by (for most sprayers) turning the tip of the nozzle as far counter clockwise as possible.  Stop spraying every few minutes to pump up the sprayer and shake thoroughly.  Spray from 8-10 inches away from the leaves.  Spray underneath the leaves starting at the bottom of the bush and working up.  Then give one quick spray on top of the leaves.  Spray until just before drops start to roll off the leaves.  Spray the ground underneath and around each bush.

After you use up all the spray material you prepared (if necessary, spray any excess on your lawn, but do not dump it down the sink or into a storm drain) rinse out the sprayer with hot water, and run some hot water through the sprayer to clean the working parts.