Irises are surprisingly easy to grow, but advice online must be modified for the Mojave Desert and southern Nevada. If local weather is hotter, cooler, or wetter than usual, adjust your garden care accordingly (Check the local National Weather Service offices for current and forecast conditions)

Regardless of the time of year, add these to your daily inspection of your garden:

Remove dead outer leaves.
Spray for aphids and roly-poly bugs as you find them. Natural pesticides only.
If leaves turn yellow, fertilize with iron.
Pull weeds so they don’t compete with the irises for nutrients and water.

January

Spread triple phosphate (like 0-30-0 or higher) fertilizer lightly around irises and carefully scratch it in around the rhizome. Water thoroughly.

February

In the last week of the month, fertilize with a balanced 15-15-15 fertilizer, scratch in if you’re using granules, and water it in. Plant chilled rhizomes when overnight temperatures are consistently 50-60 degrees.

March

Remove dead outer leaves. Spray for aphids as soon as you see them. Look for natural beneficial predators like ladybugs or use natural pesticides or wash well with high pressure water. Start looking for buds.

For more information about home gardening, please get in touch with the Master Gardener Help Desk (702) 257-5556 or extensionClarkMG@unr.edu (great for sending photos with your questions)

Fertilizers:

Fertilizer makes up for a lot of the shortcomings of southern Nevada soils. Commercial fertilizers are typically labeled with three numbers, such as 15-15-15. They represent nitrogen, phosphorus, and potassium, abbreviated “NPK”.

Nitrogen (N) stimulates root growth and encourages green leaves. Most forms of nitrogen in fertilizers are water-soluble, so they wash away if you overwater. Too much nitrogen gives fast but unsturdy growth, which can lead to soft leaves that are susceptible to bacteria, insects, and extreme weather.

Phosphorus (P) enables root growth and flowers (and then fruit and seeds). Some forms are insoluble, but in a commercial mix, phosphate compounds overcome this.

Potassium (K). Its superpower is water movement, so it promotes root growth and overall plant hardiness through disease and pest resistance. Since nitrogen, phosphorus, and micronutrients are water-soluble, potassium is crucial to moving those things “all around” any plant.

Choose your fertilizer with the end result in mind.

Robinson, M.L. Ochoa, C. and Lloyd, S. 2025, Iris: a year-round in the desert southwest, Extension, University of Nevada, Reno

Extension Associated Contacts

Susan Lloyd

M.L. Robinson

Also of Interest:


Pollinator Plant Lists Lists of pollinator-friendly plants for Nevada. Jensen, C. 2025, Extension, University of Nevada, Reno
Hemp Basics: Anatomy of a Female Hemp Plant This publication provides readers with a thorough introduction to the anatomy of the female hemp plant, which is grown and harvested for many uses. The major parts of female hemp plant are discussed and displayed in a diagram. McGue, L., Morawska, M., Robinson, M.L. and O'Callaghan, A.O. 2021, Extension, University of Nevada, Reno, FS-21-97
Nevada Noxious Weed Field Guide – Flowering rush Flowering rush is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed. Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
Cold-hardy cacti A list and description of cold-hardy cacti. Fisher, J. 2018, Reno Gazette Journal
Hydrangeas in Northern Nevada Are there varieties of hydrangeas that will grow here? Yes. Will they thrive? Rarely, under average garden conditions. JoAnne Skelly 2016, Extension \| University of Nevada, Reno

Associated Programs

Master Gardeners of Nevada

Program trains local gardeners to provide research-based horticulture information to Nevadans

Pink, yellow, and purple native flowers in landscape surrounded by rock terrace landscaping

Home Horticulture Certificate Program

The Home Horticulture Certificate Program was developed by the University of Nevada, Reno Extension Horticulture team to provide basic horticulture education to homeowners, educators, and anyone interested in learning more about the Nevada landscapes, plants, and more.

Master Gardeners of Clark County

Serving Clark, Lincoln and Southern Nye counties gardening needs.

Iris: a year-round in the desert southwest