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"Designing a New Perennial Garden" Beautiful perennial gardens have as their backbone good design. When designing a new perennial garden, it's important to first know the growing conditions of the garden and the cultural requirements of the various perennials. After all, if the plants aren't suited to the growing conditions of the garden, then the overall effect will not be achieved no matter how good the design is. Just because a plant offers the right flower color or foliage texture does not necessarily mean it will grow well where planned. Once the cultural conditions and growing requirements of the perennials are matched, then it's time to combine the plants in a pleasing way to best show off their attributes. A garden planted with an assortment of perennials allows for good plant combinations in all the different seasons. Since each perennial has its own blooming period, by choosing a few perennials from each of the four seasons it's possible to design a perennial garden that provides year 'round color and interest - even in seasons not normally associated with flowers.   In addition to knowing the bloom period of each perennial, it's important to know the eventual size of each plant and allow for adequate spacing when designing the perennial garden. Knowing how a plant grows - clump forming, climbing, spreading, etc. - also helps determine where it belongs in the garden. I am a strong advocate for planting in groups of odd numbers - three, five, seven, or more if space permits. This creates a sense of fullness right away in the garden and avoids the "polka-dot effect" of having one plant here and one plant there in the garden. Repetition of plants or plant patterns also helps create a pleasing display. It's especially nice in a perennial border. Where the perennials are planted in the garden depends on the type of garden and how it is viewed. A perennial border viewed from just the front would have the tallest plants along the back of the border with shorter plants in front and the lowest-growing plants used as edging plants. In a perennial garden designed to be viewed from all sides, the tallest plants would be in the center of the bed with the shorter plants stepped down from the center out to the edge. Click here to browse Pernell Gerver's selection of perennials through the four seasons in his Online Store.

by Pernell Gerver

"Virus May Cause Distorted Delphiniums" Q. For many years I have grown delphiniums in my garden, but in the past eight years many of them have been plagued with a disease that distorts their leaves and often their blossoms. As soon as this is detected the plant is destroyed and replaced, but soon half the replacements are also victimized. Can this be controlled, or should I just abandon these beauties? They are the backbone of my garden. Thank you. A. Delphiniums are tall, stately perennials that bloom in summer in a range of colors including pink, blue, violet, and white. Their tall flower spikes rise above the flower bed to provide an elegant vertical accent. Delphiniums range in height from three feet tall to over six feet tall. They are a short-lived perennial, but are easy to start from seed. From your description, it sounds as if your delphiniums may be infected with a type of virus. There are many viruses that affect delphiniums, including aster yellows, delphinium ring spot, mosaic, and beet curly top. The symptoms of these viruses include stunted or distorted leaves. The foliage may also be yellowed and have spots or streaks. Often the entire plant is stunted and has small flowers. Viruses can be spread by insects such as aphids. As the insect feeds on the plant it spreads the disease from plant to plant. Treat for aphids to prevent the spread of disease. One of the easiest ways to remove aphids from the plant is to spray the plants with Neem Oil, an organic, three-in-one spray. In a serious infestation, spray every 10 days or so. Unfortunately, there is no cure for the viruses that infect delphiniums. The best way to control them is to remove all the affected plants and dispose of them. Do not add the diseased plants to the compost pile. Be sure to disinfect any tools used to remove the plants. Spray the tools with rubbing alcohol or a 25 percent bleach and water solution. Wash your hands thoroughly before touching any other plants. Click here to order Neem Oil from Pernell Gerver's Online Store. Click here to submit gardening questions for Pernell Gerver's online Q & A column. Click here to read previous online columns in the archives.

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