Humboldt Rose Society

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Updated 4/24/07

Spraying Tips For Lazy Rosarians
By Dr. Stan Baird

Of all the many tasks involved in growing roses, there is nothing I hate worse than spraying! I am definitely a lazy rosarian, so in that sense, perhaps I am qualified to address this subject. We sometimes read advice in The American Rose that we should promote the idea that our beloved roses are easy to grow! Who are they kidding? Roses are subject to a dismaying number of pests and diseases from crown gall to dieback to downy mildew. I am definitely in favor of doing everything we can to promote roses, but I think we should be honest and tell the beginner that roses do require lots of care. But in return, they reward us with glorious blooms that are the epitome of horticultural elegance. As such, they are well worth the regular maintenance they require. What is more soul satisfying than to stroll through the rose garden and admire the perfection of those elegantly formed roses? I try to keep that thought in mind whey my back hurts from spraying 150 bushes.

Now to that least favorite of tasks - spraying! Ideally, we should do our first spraying soon after pruning. And if the bush still has some of last year’s leaves hanging on, they should be removed and destroyed. Rayford Reddell in his book, Growing Good Roses, tells us that removing last season’s leaves causes dormant buds to swell, making it easier to tell where viable buds exist. The classic recommendation for dormant spraying is Volck oil. But Volck oil must be used soon after pruning and before those new leaves begin to show. Those sensitive new leaves do not take kindly to Volck oil and will be severely burned. I must confess that I often don’t get my dormant spraying done soon enough to use Volck oil! But take heart; all is not lost! Just mix up a systemic fungicide such as Funginex or Banner Maxx and your favorite systemic insecticide at the recommended dilution rate and that will make an excellent dormant(?) spray. Volck oil has no magical properties and no advantage over your summertime spray materials except that it does control scales. But scales are rarely a problem in our area. Only once in 44 years of growing roses in Humboldt County have I encountered scales on my roses. But before that first spraying, whether with Volck oil or a systemic spray, clean up the dead leaves and other litter around each bush. A few little pieces of dead leaves are not a major concern if you spray the soil around the base of each bush. To save time when spraying the soil around the bush, turn the nozzle of your spray wand until a coarse spray is produced. This will greatly reduce the time required to really saturate the soil around each bush.

We now have a wide selection of fungicides and insecticides for roses. I prefer systemic sprays because the tend to be more effective. Some of the newest systemics work much longer than older products. (A systemic fungicide or insecticide is one which is absorbed into the plant tissue and thus protects the entire plant much longer than most non-systemic spray material.) The favorite systemic insecticide of this lazy rosarian is Banner Maxx. “But it’s so expensive!” you say! Would you believe it’s less expensive than Funginex. On the initial purchase, the Rosemania price of $67.95 per pint may send you into sticker shock. BUT WAIT - how long will that pint of Banner Maxx last? The recommended dilution rate is only 1/3 of a teaspoon per gallon and the recommended frequency is only once every two to three weeks. (I have found once every three weeks to be adequate except in the wettest spring weather.) At the recommended dilution rate, that pint of Banner Maxx will make 288 gallons at a cost of only 24 cents per gallon. Even if I spray with Banner Maxx every two weeks and use ten gallons of mixed spray material each time I spray, the cost of using Banner Maxx comes out to only $4.80 per month.

By contrast, Funginex is mixed at a dilution rate of one tablespoon per gallon and should be applied once a week. Thus, one pint of the Funginex concentrate makes only 32 gallons. The last bottle of Funginex I bought cost $20; thus, the cost per gallon of mixed spray would be 63 cents per gallon compared with 24 cents per gallon for Banner Maxx. Thus, with Funginex, I will use 40 gallons of spray per month as compared with 20 gallons per month with Banner Maxx. So if I use 10 gallons of mixed spray each time I spray with Funginex and spray once a week, it will cost me $6.30 each time I spray for a total of $25.20 per month. Banner Maxx wins the budget battle hands down - and it’s just the thing for lazy rosarians like me who hate spraying!

For insect control, I prefer Cygon 2E (dimethoate) to Orthene. The reason is that I have found Cygon gives protection longer than Orthene. Also, Cygon can be used as a soil drench, in which case it will kill every aphid on the bush in 24 hours. Cygon is not readily available at our local nurseries, but it is available by mail order from Primary Products.

In addition to blackspot, rust, powdery mildew, and aphids, botrytis can be a serious problem in Humboldt County’s damp climate where nightly fog provides a hospitable climate for a variety of fungi. Botrytis is a fungal disease that causes the edges of rose petals to turn brown and if not controlled may cause the entire bloom to turn brown. The fungicide for botrytis most highly recommended by experts is Chipco 26019, a wettable powder. (Chipco is also the most effective fungicide for botrytis on daffodils.) It can be ordered from Primary Growers or B T Growers. Both Primary Growers and Rosemania have web sites at the following URL’s: www.primarygrowers.com and rosemania.com. With a credit card, you can order by phone and the product will be on your doorstep in a few days. Before spraying, always be sure you have adequate protection to avoid skin contact with the spray material. A respirator is probably the safest device to prevent inhalation of the spray mist. However, I find a respirator stifling on a warm day. As an alternative, I use a plexiglass mask which I ordered from an agricultural supply company. It has adjustable straps and fits over the head. The plexiglass portion is curved around the face to provide complete protection and the opaque portion even protects the chin. It is far more pleasant to use than a respirator. You should also wear long sleeves and avoid getting significant amounts of spray material on your pants legs. I have a protective device for my pants legs which is made of a chemical proof fabric and works much like chaps. These “chaps” are easily pulled on over your pants and fastened to your belt loops.

Try to avoid spraying on a windy day as the wind will tend to blow mist from the sprayer onto you face and clothes. Also, mix your spray material fresh each time you spray. Do not save left over spray mix for use the next time you spray.

One of the most neglected aspects of spraying is getting at the underside of the foliage. It is all too easy to become so involved in spraying the tops of the leaves that you become careless about spraying the underside. The underside is actually more important that the top, for the underside of the leaf absorbs the spray much more readily than the top. This is especially important when using systemics I have formed the habit of spraying the underside of the foliage first so that I do not neglect it. I also feel it is important to spray very thoroughly, and where a fungus disease such as botrytis has become a serious problem, it is advisable to drench the soil under the bush as well as the leaves and canes. I have found if I spray very thoroughly, I can spray less often. I have also found that if I spray very faithfully up until the middle of June, I can then spray less often the remainder of the summer. I like to spray to the point of some run off. While this is frowned on in much of the literature, I have not found this to cause problems with spray burn in our cool maritime climate. But to be on the safe side, I usually tap the canes with the spray wand to knock of any accumulated spray material at the tips of the leaves.

A few reminders for those of you who are planting new roses: Remember to put a handful of superphosphate in the bottom of each hole because phosphorus, which is essential for strong roots, does not move through the soil readily and you need to get it down where the roots can use it. Also, mix several handfuls of alfalfa pellets into the soil. The alfalfa contains a plant hormone which stimulates growth. With bare root roses, avoid letting the roots dry out. The roots can be soaked in water for a day or two without damage. Be sure you dig the hole deep enough to accommodate the roots as they grow out into the soil. That means holes about 18" deep and 30"wide. If you have the heavy black clay so prevalent in this area, take most of the soil out of the hole and pile it on a plastic tarp (available at most hardware stores at a modest price) or a large piece of plastic and mix in copious amounts of organic material (up to 50 percent) such as redwood compost, Supersoil, and well composted steer manure. Check steer manure carefully before buying it. When you squeeze the plastic bag, the contents should feel loose and fluffy. If not, the manure is either not well composted or it is very wet. Wet steer manure will dry into hard cakes which are unusable. Beware of steer manure which is not well composted as it may burn tender new roots.

Finally, I must confess that I am NOT a consulting rosarian. I am writing this article because our diligent and dedicated editor asked me to. But I have been rasing roses for quite a long time. I began with roses on an Iowa farm while still in my teens. Iowa’s ferocious were tough on hybrid teas that were not hardy enough to stand sub-zero temperatures. But that Iowa farm had wonderful rich, black loam that I would love to have in my Blue Lake garden. Then after a period of years during which I lived in rented apartments with no opportunity for gardening, I moved to Humboldt County in 1958 and resumed growing roses and a wide variety of other ornamentals. I joined the Humboldt Rose Society one year after it was organized and did the schedule for our first show. But learning about roses never stops - there is always more to learn. If anything I’ve learned and shared here is helpful to some of you, this article will have achieved its purpose.