March 23, 2017

Revised Hort and Home Pest News Website

The Horticulture and Home Pest Newsletter was created 30 years ago as a spin-off from the Insect, Weed & Plant Disease Newsletter.  In 2005, HHPN became an electronic newsletter after 18 years as a printed, mailed-by-subscription newsletter. 

Plant and Insect Diagnostic Clinic Update - March 23, 2017

structures (Stigmina signs) observed under microscope magnification.

The following are highlights and updates about samples and questions recently received in the Plant and Insect Diagnostic Clinic. Visit the PIDC's Facebook page to ask questions and for updates and more pictures. For more information on a particular disease or insect problem listed, follow the article cited.

Crown And Root Rot In Bedding Plants: Pythium spp.

Note discolored roots (left). Note microscopic pathogen structures (water mold signs) on the root tissue (right). Photo credit: Lina Rodriguez Salamanca, Plant and Insect Diagnostic Clinic

Popular bedding plants such as geranium, petunia or coleus may develop crown and root rots.  Pythium is one of the pathogens that we have encountered in several plant samples this spring. Symptoms can vary by plant age. For example, young plants may look discolored and die suddenly, a common syndrome known as damping off. This syndrome can also occur in vegetable transplants grown indoors and outdoors.

Unique Trees and Shrubs to Plant this Spring

With the arrival of  spring, many people across the state are eyeing their local nurseries, greenhouses and garden centers for trees and shrubs to plant to spruce up their property. However, the process of selecting a species can be overwhelming, with dozens of choices at greenhouses and exponentially more available through mail-order catalogs. With infestations of Emerald Ash Borer in the state, it is logical to avoid planting the various ash species.

Pruning Hydrangeas

large white flower of the Annabelle hydrangea

In order for shrubs to perform well in the landscape, home gardeners must prune them properly.  Proper pruning helps maintain plant health, control or shape plant growth, and stimulate flower development. 

Three species of hydrangea are commonly grown in Iowa.  Pruning practices are based on the growth and flowering characteristics of each species. 

Caring for Hostas in Spring

Close up of variegated leaf of Hosta 'Paradigm' a large, chartreuse leaf with dark green edge

Spring is here, and hostas are a popular part of outdoor landscaping plans. They are easy to grow, but certain steps in planting and dividing them must be followed in order to ensure optimal performance.  Learn more in the Iowa State University Extension and Outreach Yard & Garden news release from March 23, 2017.

Emerald Ash Borer Found in Greene and Wayne Counties, Iowa

Map of Iowa showing current distribution of confirmed EAB infestations as of March 9, 2017.

The emerald ash borer, Agrilus planipennis, an exotic species of beetle that attacks and decimates ash trees, has been confirmed in Greene and Wayne counties. EAB has now been confirmed in 43 counties in Iowa.  See the map below and read more about the most recent discoveries in the Iowa State University Extension and Outreach news release from March 10, 2017. 

Preparing Garden Soil for Spring Planting

When it's time for planting the spring garden proper care must be taken to ensure the soil is ready for growth. That means fertilizing soil, testing it and, perhaps, applying materials like lime.  See the Iowa State University Extension and Outreach Yard & Garden news release from March 15, 2017, for information of these and other soil-preparation topics.