March 2024 TRS Clinic

Spring Chores for March & Early April

Cleanup / Fungicides / Planting

By now we should be finished with the pruning of our existing roses (or at least well on the way.) There is only a slight chance of frost, and if we do get one, it is not likely to be hard or prolonged in nature. In our yard, the forsythia and the quince are blooming, and the daffodils are in full flower. This means it’s time for us to get out & finish up our pruning.

Once the pruning is “finished” we should make sure to get clean up & dispose of any rose debris in our garden, put on that lime if we have not done so, and lay down several inches of fresh mulch (in mulch we trust!)

Protection against fungal spores

I believe that fungicide spraying of a rose garden at this time of year is a good way to keep black spot & powdery mildew at bay later in the growing season. This is not to say that it will not be necessary to keep up our disease prevention program throughout the season, but it is a reminder that we are ahead anytime we can reduce the amount of fungal spores present in our garden. In other words, at this time of year the best defense is a good offense . . .

There are many fungicides that are touted for their utility on roses. In general, these are of 2 types:

• Those that kill fungal spores – and

• Those that inhibit the ability of the targeted fungal spores to penetrate the surface of the rose leaves.

At this time of year, it is the “spore killers” that we need to use. Some popular choices are mancozeb, manzate, and fore. (All are essentially the same compound.) The packaging & brand names of familiar products seem to change each year . . . Many are the same products that we used to purchase as Daconil and the active ingredient of chlorothalonil. Daconil is back on the market from several different manufacturers.

These products are sanctioned for use on many vegetables, fruits, roses, flowers, shrubs, & trees. Check the label for a specific species list. As always: follow the instructions on the label – especially those giving dosage rates & those dealing with SAFETY. These chemicals are listed within the “WARNING” category, but be sure to follow all the safety instructions – especially for eye protection. Irreversible eye damage can result.

We will now talk about some of the most effective systemic fungicides that are readily available to us all. These are generally NOT for use on any edible plants.

Opinion on just what is “the best” SYSTEMIC fungicide for rose diseases changes as time progresses. Many of the chemicals in use when I started rose growing are no longer available (or legal!) Currently the “top” product is Banner Maxx and before that we all tried to get & use Rally or Eagle. These products are available from nursery suppliers and online sources, but aren’t easy to buy locally. The good news is that you can go to local nurseries, garden centers, & hardware stores and buy the same chemical with a different name and a different concentration of the active ingredient.

Banner Maxx = 14.3% propiconazole but Fertilome liquid Systemic Fungicide = only 1.55% propiconazole (and Bonide makes one too.)

Rally or Eagle 20EW = 19.7% myclobutanil but Immunox = only 1.55% myclobutanil

So, again, the active ingredient is the same, but with very different dosage recommendations. Re-read the label & measure carefully.

Planting new roses

At any time now we can continue to plant roses. This will be a topic for our discussion session during the March TRS meeting – but a quick reminder about some planting basics begins here.

Choose an area with lots of sunlight, good drainage, & no intrusive roots from other plantings. Good air circulation at the site will minimize black spot, mildew, & rust. If existing drainage is bad, consider installing raised beds.

If you’ve purchased bare-rooted roses, they should be soaked overnight in water before planting. Damaged roots should be removed and all ends should be snipped to promote hair root growth. If your rose is in a container, follow the the instructions below – but try to keep the root ball intact.

You can plant your rose in the ground or in a container. In the ground, the hole should be about 2 ft in diameter, and 2 ft deep. This closely corresponds to a 15 gal container. If you plant the rose in a container, plan on repotting it with fresh soil & amendments after 3 years.

After removing the soil from the hole, replace it with 1/3 garden soil, 1/3 organic material (maybe Cedar Grove Compost, Prep, or Super-Doo) and 1/3 sand. If your garden soil is particularly bad, substitute good potting soil like Tagro Potting Soil. For best results, add the following amendments to the hole. (This is Dennis Konsmo’s recipe.)

Super phosphate (0-45-0), Dolomite Lime (if in doubt, test the pH), Gypsum, Kelp Meal, Fish Meal, Cottonseed Meal, Bone Meal, Blood Meal, and Alphalfa meal. (Feel free to double or triple up on the Alphalfa meal!) The most essential of the above listed amendments are the super phosphate, Dolomite Lime, & Alphalfa meal. Don’t add fertilizer at this time . . .

Once the hole is ready, form a mound of soil in the center of the hole & drape the plant over the mound with the bud graft at ground level. Roots should be spread out naturally. Gently fill with soil while holding the plant upright. Firm the soil gently with your hands, NOT YOUR FOOT. Water thoroughly. After that, mound the soil over the stems to 10″ to conserve moisture. Remove the mound in about 2 weeks time (or when danger of frost is past) with a gentle stream from a water hose. The metal name tag on a wire can injure the cane it’s mounted on, so either replace the wire with a monofilament loop or put the tag on a stake.

Spring Tonic

In a 32 gal garbage can (with lid) in a mesh bag, add:

• 10-12 cups of Alphalfa Meal (or pellets)
• 2 cups of Epsom Salts (MgSO₄)
• 1/2 cups of Chelated Iron
• Fill the can with water & add the lid (for smell)
• Let this ‘steep’ for a week or so, stirring every 3 days.

The alphalfa meal can be used in a 2nd batch, but replenish the “additives”.

This is your tonic for use every 3 weeks until the Rose Show, added at the base of the bushes, then watered in. (This is often called side-dressing.)