Summer Garden Issues

Summer is officially here, and with it familiar issues for Colorado gardeners. Do you have some of the same questions that are coming into the Broomfield Horticulture Helpline? Read on for answers!

Why are my tomato leaves yellow?

Some yellowing of lower leaves is normal as tomatoes grow, but you can rule out common issues by learning what signs and symptoms to look for. Check the leaves for insects. Aphids and white flies can lead to yellowing leaves and cause the plant to produce a substance called honeydew, which makes the leaves appear shiny and sticky. Psyllid nymphs can be found hiding on the underside of leaves, and leave behind what look like small granules of sugar or salt. When they feed on tomatoes, they cause yellowing of leaves, sometimes with characteristic purple veins. If you don't notice the insects, you may be extra disappointed later in the season when you discover that the plant produces abundant, but tasteless, fruit - another effect of psyllid damage. Find management tips for these and other common tomato issues in the CSU Extension Fact Sheet Recognizing Tomato Problems.

What's chewing little holes in my vegetables?

Well, it depends on the vegetable, the season, and the damage (check out this handy matrix showing which insects affect each vegetable plant!). If you are noticing similar damage on many different types of vegetables in your garden, you are looking for a fairly indiscriminate chewing insect - in this case the flea beetle. Flea beetles chew distinctive “shotholes” in leaves, and between three common types of flea beetles found in Colorado gardens, they can affect most of our favorite plants for most of the season. Learn more about flea beetle management in this CSU Extension Fact Sheet, or this short video from Grow and Give Colorado.

Why is my lawn yellow?

This late spring and summer have been extra hot with no end in sight, and many lawns are suffering. While there are some common and frustrating lawn diseases out there, their presence is connected to lawn water and maintenance practices. Many lawn questions can be linked directly to watering issues with no other cause, so don’t jump to conclusions. Check your irrigation first - it could be as simple as a broken sprinkler head! Broomfield residents (and many other communities) are eligible for a free irrigation audit through Slow the Flow Colorado. Sign up today!



Q. I have a problem with a tree in my yard. Who can help me with this?

A. Broomfield Master Gardeners have the training to troubleshoot most common tree issues, free of charge! You can contact them via:

• Email: broomfieldmg@colostate.edu
• Phone: 303-464-5554
• Walk-In: Visit the Broomfield Extension Office on Tuesdays and Thursdays from 9 a.m. to 1 p.m., when Master Gardeners are available. 
• Please note we will not have Master Gardeners on site during the week of July 1st due to the holiday.

Sharing a few photos of the affected tree through email or during a walk-in visit, along with a thorough description of the issue and how the tree has been maintained, will allow the Master Gardeners to help you most effectively.

If the Master Gardener(s) on duty feel the tree issue may warrant a closer look, they may offer you the option of an on-site visit by our dedicated Tree Team Master Gardener volunteers for a $25 fee. A site visit is offered at the discretion of the Master Gardeners, but can be a helpful option for more complex tree problems. 

Alternatively, you can search for an ISA-credentialed arborist in your area by visiting www.treesaregood.org/findanarborist/findanarborist. Please contact an arborist, rather than a Master Gardener, if the tree in question poses a hazard to people or nearby structures.

If you're interested in becoming a Master Gardener in Broomfield,

please visit the Colorado Master Gardener website for more information.