Gardening in Larimer County

Ah, summer! Time for lemonade, evening concerts, early morning walks and declining flowerbeds!  Diagnosing the problem is the first step to repairing it and answering some of the basic questions can help you solve August’s peskiest problems.

Bedding plants and flowers

*  Note symptoms in detail. The best time to examine life in the garden is in early morning.

*  Is only one plant involved or does your entire garden look bad?

*  Do plants have a “talcum powder” covering? This is powdery mildew, a very prevalent fungal problem in Colorado. Plants that are too close together combined with poor air circulation encourage the disease formation. Addressing the above situation will fix the problem if caught before approximately 50% of the plant is affected. Otherwise, many perennials will come back next year if clipped close to the ground this fall.

*  Are plants leggy? Too much nitrogen fertilizer and not enough light can be the cause. Prune the plants back to maintain a bushier growth habit.

*  Are the leaves curled? Aphids feeding on the leaves could be the culprits here. Chewed leaves are often the result of slugs or grasshoppers feeding and spider mites or leafhoppers often cause speckled spots. Webbing is a sure sign that spider mites are present.

*  Are plants yellowing? The most likely causes are over watering or iron or nitrogen deficiency. Watch your fertilization and watering schedules.

For more help diagnosing your plant problems, call the Larimer County Cooperative Extension office at 970-498-6000.  By having done the detective work ahead of time, Master Gardeners can more quickly get to the bottom of your dog day gardening problems.

Question: I’ve noticed that my honeylocust tree seems to be losing its leaves already. Some of those leaves seem to be smaller than the rest and have a bronze color. What could be wrong?

Answer:  Sounds like you may have a spider mite problem. These barely visible creatures attack street trees, and other dry and drought-stressed sites. Regular watering during hot months helps reduce their population. Natural predators (predatory mites or thrips) can help reduce mite populations, but sometimes chemical controls are needed. Miticides are available at your local nursery and garden center but be sure to read and follow the label when using any pesticide.

Question: I’m new to Colorado and very frustrated with gardening here. I used to have a green thumb. Now I can’t even grow simple bedding plants.  Help!

Answer:  Low humidity, fluctuating temperatures, heavy alkaline soil, and drying winds are but a few conditions that make it challenging, for sure. Gardeners who are patient, select plants that do well here, amend the soil and develop microclimates can be amply rewarded.  Be gentle on yourself! Go to the library, peruse local nurseries, talk to your neighbors who have enviable gardens. Write down your frustrations and call a Master Gardener at the Larimer County Extension Office at 970.498.6000.

Question: I have a huge backyard that is mostly dead grass. I like the idea of planting wildflowers on much of it. When is the best time to do this?

Answer: Fall is a good time to sow wildflower seed because subsequent cold and snow (moisture) will promote germination the next spring. Choose a seed mixture that matches your site conditions, add moisture if it is a dry winter, and sit back to enjoy.

Look to ornamental grasses to add interest to your landscape.  There are grasses that do well in dry conditions such as Indian grass and prairie dropseed.  Grasses that do well in moist conditions include moor grass and Japanese blood grass.  When planning to add ornamental grasses to your yard, check to see if they do best in warm temperatures or in cooler temperatures.  This will help you make the best selection for your garden's location.

Try to include edible flowers into your landscape.  These include marigolds, calendula, and nasturtiums.  Flowers can be used in many recipes.  Roses for example can be used in flavored vinegar, flavored butters and tea.  Petals can be candied and used to decorate cakes.  Don't spray with pesticides if you are growing flowers for consumption.  Keep in mind that some flowers are poisonous.

When you buy tomato plants in the spring, you'll notice that the label will specify "determinate" or "indeterminate."   Knowing the difference can help you plan your harvest.  Determinate means that the plant will grow to a given height and then put its energy into producing a crop.  Celebrity is a variety that you can grow if you want a large crop all at once for preserving.  Indeterminate tomatoes grow and produce until frost.  They might need to be pinched back to keep them under control.  If you want salad tomatoes all season, then these are the tomato varieties to look for.

The authors have received training through Colorado State University Cooperative Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.

Gardening and Insect Fact Sheets are available on-line by clicking HERE.

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This page updated:  March 28, 2003