February 10, 1993

Pruning Large, Overgrown Lilacs

The common purple lilac is a tough, reliable shrub that may reach a height of 15 to 20 feet. Unfortunately, as lilacs mature, the shaded lower portions of the shrubs usually lose their leaves. As a result, large, overgrown specimens are often leggy and unattractive. Old, neglected lilacs can be renewed or rejuvenated by pruning. Home gardeners can choose between two different pruning methods.

Tomato Spotted Wilt Virus in the Greenhouse

Tomato Spotted Wilt Virus (TSWV) is a destructive virus disease that affects a wide range of plants including certain bedding plants, floral crops, and vegetables. It is now known that there are two different but closely related viruses that cause greenhouse symptoms. The most common virus, previously known as TSWV-I (Impatiens isolate), is now known as Impatiens Necrotic Spot Virus (INSV). This virus causes problems on plants such as garden impatiens, New Guinea impatiens, cyclamen, cineraria and gloxinia.

Working with the Right Tools

Late winter or early spring is an excellent time to prune many trees and shrubs. The keys to pruning are a basic understanding of pruning techniques and the use of proper tools. There are various types of pruning tools. The size of the plant material determines the best tool for the job.

Landscape Lighting

Occasionally questions come to Hortline regarding the use of security or landscape lighting. Clients are concerned about the effects this lighting may have on plants in the landscape. To understand how these types of lighting may affect the plant we need to understand how plants use light. Light influences plant growth through quality (wavelength or color of the light spectrum), intensity (irradiance), and lighting duration. Light visible to the naked eye occurs in the wavelengths from 380 to 760 nanometers (nm). The wavelength of 380 nm is visible to us as violet.