Western (TX, AZ, NV, CA, NM, OK)

Western growers are in the most variable disease environment of any region, and the first week of June captures that variability sharply. Arizona and Nevada low-desert growers are in peak heat. East Texas is in Gulf Coast disease conditions. Coastal California has marine layer. What you need to watch this week depends heavily on your specific location.

Arizona and Nevada Low Desert: Phoenix, Tucson, Las Vegas

Your disease pressure this week is low compared to every other region. Dry heat does not support fungal pathogen development. The alert this week for low desert growers is heat stress on plants in dark containers that are superheating root zones during 100-plus degree days.

Check containers for heat accumulation. If a black or dark-colored plastic container is sitting in full sun in Phoenix in June, the root zone temperature can exceed air temperature by 15 to 20 degrees. At those temperatures, root cell damage is possible even on heat-tolerant genera. White containers, container feet for airflow, or shade cloth on the container body — not the plant — are the solutions.

Pachypodium in Arizona conditions in June are in their most natural growing environment of any U.S. location. Full sun, dry heat, and excellent drainage produce the fastest caudex development you will see anywhere in the country. If you are not growing Pachypodium in the Phoenix or Tucson areas, you are missing the best Pachypodium climate outside of Madagascar.

Texas: Houston, San Antonio, Dallas, Hill Country

East Texas and the Houston metro are Gulf Coast disease conditions. Apply the Gulf Coast protocol in full — Plumeria rust is active now, Adenium anthracnose pressure is elevated after rain events, and drainage is the primary management tool.

Dallas and the Metroplex are entering the dry heat period that compresses disease risk compared to the humid east. Anthracnose is possible after thunderstorm events but less persistent than in Houston. The watch item this week in Dallas is sunscald on plants that went outside during the recent heat spike, particularly Adenium and Plumeria that were acclimated under grow lights through the winter.

Hill Country growers have a microclimate advantage — lower humidity and better airflow than either coastal or urban Texas. Your disease risk profile is the lowest in the state. Focus on drainage and appropriate sun exposure for your specific elevation.

California: Coastal vs. Inland

Coastal California growers from San Francisco through the Monterey Peninsula and the cooler zones of Los Angeles County should apply Pacific Northwest protocols. Marine layer conditions, cool nights, and delayed heat accumulation mean your June 1 disease conditions more closely resemble inland PNW Zone 8 than Southern California desert.

Inland California — Sacramento Valley, Inland Empire, San Diego inland valleys — is in active summer heat. Your disease pressure this week is moderate. Anthracnose is possible on Adenium during or after rain events. Sunscald risk is real for recently transitioned plants. Full sun and fast-draining media are your management foundation.

Southern California coast — Los Angeles basin through San Diego — has the best overall Plumeria conditions in the continental United States outside of Florida. Rust management is relevant but less critical than in Gulf Coast conditions. If you do not have Pachypodium in your Southern California collection, this is the week to start.

New Mexico and Oklahoma

New Mexico growers are in low-humidity conditions similar to Arizona. Disease pressure is low. Heat management and drainage are the primary concerns this week.

Oklahoma growers are in a variable week — if a Gulf moisture surge is in place, disease conditions approach east Texas. If a dry westerly pattern dominates, conditions are more similar to the Plains. Check your last five days of weather. Humidity above 70 percent overnight consistently means you should apply the Gulf Coast disease watch protocol.

What We're Growing With — Western

Desert Oasis Summer Top Dress Media — Fully relevant across all Western zones in June. Texas, Southern California, and desert Southwest growers should apply now. Coastal California growers: apply at first sustained warm stretch.

Desert Oasis Potting Media — Critical for container growers managing root zone temperatures in desert heat. Fast drainage also means fast cooling of the root zone between waterings — an advantage in triple-digit conditions.

Desert Oasis Spring Jump Start — Apply now for Texas and Southern California. Still relevant for coastal California and high-elevation New Mexico growers entering their growth window later.

Desert Oasis Spring Top Dress Media — Coastal California and high-elevation Western growers whose season is still ramping up in June will benefit through mid-month.

Full product details: americanadenium.com/pages/desert-oasis-products

Cheers, 

Michael