Iowa Master Gardeners

Japanese beetles will begin emerging soon, so here are your annual management reminders:

-Because Japanese beetle defoliation will not kill otherwise healthy, established plants, you could just tolerate the damage, even though it looks pretty bad.

-Traps are not an effective way to control Japanese beetles. They actually attract more beetles to your yard than would otherwise occur.

-Handpicking is only somewhat practical for small gardens or plants. It's a daily task that's best done in the morning when beetles are sluggish.

-If using residual insecticide sprays, you must be thorough and frequent. It will take 3-5 sprays over the 6 weeks of beetle presence, and more if it rains. Always read and follow label directions.

Learn more in this Japanese beetle article: https://go.iastate.edu/1E1KLL

ISU Extension and Outreach - Agriculture and Natural Resources

Over the last several weeks, people across the state have noticed hackberry trees shedding an alarming number of yellow leaves. This type of leaf drop is a normal response to changing weather conditions.

This April, moderate temperatures and abundant rainfall were particularly conducive for leaf production. But with the arrival of warmer, drier conditions in May, trees dropped leaves that could no longer be supported. In other words, leaves are shed to balance the water needs of the plant with available moisture. This process helps the tree conserve resources and maintain overall health.

Hackberry is not the only species that may drop leaves in late spring or early summer. River birch, boxelder, elm, and tulip poplar often display similar responses when weather conditions change. No action is needed. This is a natural and expected condition, and trees typically return to a normal appearance within a few weeks.

See more details in this news article: https://yardandgarden.extension.iastate.edu/article/2026/06/why-my-hackberry-dropping-yellow-leaves

Iowa State University Extension and Outreach ISU Extension and Outreach - Agriculture and Natural Resources

Tomorrow is Horticulture Friday on Iowa Public Radio!

Tune in at 10 am to learn from our experts and get your gardening questions answered.

Here are a few things to know when summer irrigation restrictions are in place:

- Cool-season grasses common in Iowa lawns naturally turn brown and in summer enter dormancy when rainfall or irrigation is scarce. The foliage dies back, but the crowns and roots remain alive. Most healthy lawns can survive 4 to 6 weeks in dormancy and recover when moisture returns.
- If your lawn is not yet dormant, raise mowing height to 3.5-4 inches. Taller grass shades the crown, cools the root zone, and promotes deeper, more drought-tolerant root growth. Do not mow dormant turf, as this can cause damage.
- Hold off on fertilizing dormant lawns. Nutrients will not be taken up by the plant, and applications should wait until conditions improve in early fall.
- While lawn irrigation is restricted, newly planted trees, shrubs, vegetables, and other garden plants can be irrigated responsibly as needed.

Find more information here: https://www.extension.iastate.edu/news/iowa-state-university-extension-and-outreach-offers-lawn-care-guidance-amid-central-iowa
Other watering resources: https://go.iastate.edu/watering

Iowa State University Extension and Outreach

Fact or Myth?
Some lawn alternatives need less water than traditional grass.

Fact! Native grasses and sedges are more drought‑tolerant and can stay healthy with far less irrigation.

Want to learn more about low‑maintenance turfgrass alternatives? Check out the Yard and Garden website: https://yardandgarden.extension.iastate.edu/how-to/low-maintenance-turfgrass-alternatives

Do you enjoy learning and having variety in your work?

The Iowa Master Gardener Program with Iowa State University Extension and Outreach is hiring a Program Assistant II! This role also supports the Iowa Donation Garden Network.

We're looking for:
- Someone with horticulture or gardening experience/education
- Administrative, customer service, and/or public education skills
- Passion about making an impact in the community

Sound like you? We'd love to hear from you.
Apply today: https://isu.wd1.myworkdayjobs.com/IowaStateJobs/job/Ames-IA/Master-Gardener-Program-Assistant-II_R19361

Did you know composting is one of the easiest ways to reduce household waste?

Instead of sending yard debris and food scraps to the landfill, composting turns them into valuable organic matter that improves soil structure, boosts water retention, and supports healthier plants.

For more information and frequently asked questions on compost check out the Yard and Garden website: https://yardandgarden.extension.iastate.edu/how-to/composting-faqs