Now's the time to fertilize

A fun contest is being sponsored this summer -- The Biggest Tomato Contest, by the Sweet Tomato Test Garden. There will be prizes and an award for the winner. If you want to enter the contest, or just want to try your hand at growing big tomatoes, you can get some free instructions from the test garden. Call 658-7585 and ask for things you can do to grow huge tomatoes or e-mail tomato@lvcm.com and it will be sent to you.

So many things are going on right now and so many questions! In short get your fertilizers down for trees, shrubs, fruit trees, and such. Be careful fertilizing lawns. Too much will really cause a tremendous growth spurt on fescues. Get your pruning done now and dormant oil applications. Clean up dead plant debris if you haven't. Get lawns aerated and stretch your irrigations now while we still have cool weather. Make those roots go deep for the heat! Get your weeds under control now. Put down your mulch. As soon as it gets warm, everything is going to go POP!

Question: You recommended cutting shrub daisies back in early spring. What do you consider to be early spring?

Answer:That should be anytime now, as soon as we get a warm spell. The reason I mention early spring is to keep the time that it might look bad after cutting, to a minimum. Once you cut it back, you won't have much to look at until new growth appears. There may be some dead looking parts that aren't really dead. So I like to recommend waiting until you just see some new growth in the spring or right before new growth, if you happen to know when that might be.

You will probably see some new growth now as soon as we have several warm days in a row. If you stand back and look at this plant its basic architecture (main stem, and side stems) will look like a tiny tree. Or at least it should look that way. If it does and has a good distribution of side stems coming from the main stem, then just cut the side stems back removing the dead parts. If it doesn't look like a little tree then cut it back to the main stem, forcing new side shoots to grow. Then form your new tree as the side stems begin to grow, thinning out any side stems that might overcrowd the plant.

Forming these side stems will help distribute and evenly spread the load of new flowers. Fertilize!

Q: All of last year I experienced a problem with powdery mildew on my roses. Last year was the only year that I used a sealant (Elmer's Glue) to seal the cut where I had trimmed. I was guilty of incorrectly watering the roses which I have corrected. I was hoping the "powdery mildew" would go away with no water and the low temperatures during the winter months. However I still see the white stuff on the plants.

One of the professionals I had consulted told me to use a mixture of "baking soda/water" mix, but another professional told me that the plants would not survive this treatment. Now I'm really confused. Could you give me any advice for this year? I have not trimmed them back yet, and am hesitant about using "any" sealer on them after last years experience. Could you give me a recommendation as to what treatment to use to get rid of the "powdery mildew," that is still there?

A: First of all a few things about powdery mildew. This is a fungus disease that likes cooler weather and shade, but, unlike many other fungal diseases, does very well in low humidity. It grows on the surface of the leaf leaving a white powdery substance that looks like someone threw flour on the leaves. It's a perfect desert disease.

There are many forms of powdery mildews and the one that will infect roses will not infect euonymus for instance and vice versa. This means that your powdery mildew may spread to other roses but the chance of it spreading to many different types of plants is very unlikely.

The way it disperses itself to other plants is by being carried there either on equipment like pruning shears, insects like flies and through the air by splashing rain or irrigation water. This is the reason, when we see powdery mildew, we like to recommend you use drip irrigation to minimize its spread by splashing water from overhead irrigation.

Next the cultivar. Some cultivars of roses are more susceptible to powdery mildew than others. It may be that one or more of your roses could be highly susceptible while others may not be. I don't believe that baking soda will harm your plants and it may very well help to control powdery mildew but my guess is that it will control the fungus on the surface of the leaf but will not give you any long term protection.

Remove all the old foliage. Eliminate any overhead irrigation except an occasional washing of the leaves to help control mites and remove dust and dirt. If you are not opposed to chemical fungicides then I would use a fungicide called Funginex which is contained in many of the different rose systemic pesticides sold at nurseries.

If you are opposed to chemical pesticides then try the baking soda and you might consider removing the roses that are the worst problems and replacing them with roses that are more resistant to this disease.

Be sure you mulch the roses with an organic mulch, disinfect your pruning shears between cuts. You can use alcohol or bleach on the shears. If you use bleach then make sure you oil your shears right after you are finished using it.

Keep your rose beds clean. Clean up any dead leaves or debris than may be a source of this disease spreading to other plants.

As far as the Elmer's glue, it had nothing to do with this disease. I know it is recommended by many rosarians and probably for good reason. I don't use anything when I prune except a sharp shears, but I'm not a rosarian either. Some Web sites on rose care and powdery mildew are www.ianr.unl.edu/pubs/plantdisease/g979.htm and http://ohioline.osu.edu/hyg-fact/3000/3047.html.

Q: We're new to the Vegas area and I wanted to know if you're able to plant roses in the ground with rocks around it. I don't want them to burn and someone suggested I not do it. They said the same thing about the bougainvillea. Should I plant them in a pot instead?

A: No. Roses will not do well planted in our soils and mulching them with rock mulch. They may look okay for a year or two but they will slowly begin to starve for micronutrients like iron and others since our soils are basically mineral soils and will not support the kind of growth needed by roses and other nondesert plants without continual help from us as gardeners.

Even though I wouldn't recommend it, bougainvillea would probably do better in that kind of environment but they too would begin to show the signs of nutrient deficiencies like the yellowing of leaves, scorching and the rest.

Remember roses will do fine in full sun provided they aren't planted against a west facing wall, or if they are, then they should get shade in the late afternoon. Even though they are quite drought tolerant they will do better with an organic soil with good drainage and periodic watering, allowing the soil to become semi-dry between waterings.

Use an organic mulch on roses. Put the roses in the part of your yard with other higher, water using plants. Even though they can tolerate some dryness that doesn't mean they are low water use. They aren't and they should be placed near other plants with similar water requirements and on the same valve as those plants.

As far as putting either in a container, if this is done then they should be in large containers with lots of soil volume. Desert plants that can tolerate high root zone temperatures are okay in smaller containers but roses will not do well in these containers with small soil volumes. The soil temperatures will get too high and they will look very bad when we have 105 plus temperatures for extended periods. Bougainvillea is a different plant than roses and is much tougher in our desert climate except for our winters.

Bob Morris is a horticulture specialist with the University of Nevada Cooperative Extension.

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