Theresa Knutsen

Theresa Knutsen is a horticulturist and writes the Raintree Nursery newsletter "Growing Tips." Email: theresa@raintreenursery.com.

  1. Are My Apples Ripe?

    Are My Apples Ripe?
    In the Pacific Northwest, the earliest varieties are often ready to start picking by mid-August. If you are not sure when you should start checking the varieties in your yard for their ripeness, review our ripening order list on our website under plant care or consult the Raintree catalog. Some people like their fruit more green and tart, others more...
  2. Control Those Spider Mites

    Control Those Spider Mites
    Female of the red form of the spider mite Tetranychus urticae with two silk threads. The substratum is a bean leaf. Keywords : mite acari Tetranychidae "red spider mite" "two spotted spider mite" "tetranyche tisserand" arachnida Tetranychus urticae Scale : mite body length ~0.5 mm Technical settings : - focus stack of 39 images - microscope objective (Nikon achromatic...
  3. Insect and Disease Control in August

    English: female apple maggot (Rhagoletis pomonella), image taken in Lakewood, Colorado, United States (Photo credit: Wikipedia) In the July Growing tips, I wrote about the spotted wing drosophila, a recently introduced fruit fly that has been observed along the western seaboard of the U.S. and into Canada, west of the Rocky Mountains. The female fly deposits her eggs in berries...
  4. Irrigation Is Valuable During Long, Hot Summer Days

    Irrigation Is Valuable During Long, Hot Summer Days
    Drip irrigation in New Mexico vineyard, 2002 (Photo credit: Wikipedia) During the long hot days of summer irrigate as needed to provide the equivalent of 1” of rain per week (enough water to saturate the soil to 1 foot deep). Irrigation is especially valuable for newly planted trees (1-2 years) whose root systems are not fully established deep into...
  5. Organic Weed Control

    Organic Weed Control
    Malus sylvestris at Vosseslag - De Haan, Belgium (Photo credit: Wikipedia) Control weeds and keep grass short around bushes and trees and among recently planted ground covers. Maintain a minimum 3’ diameter circle for each tree or shrub that is free of competing weeds. If there are a lot of weeds coming up in your new groundcover planting, lay...
  6. Summer soil prep for spring and fall planting

    Summer soil prep for spring and fall planting
    Potted plants can be planted out — with care — if the temperatures in your area are not above the mid-80s. Otherwise, maintain your potted plants in a partial to full shade location until cooler temperatures arrive. If your area has warmed up above 80 degrees, we will be shipping potted plants to you in October — an excellent time for...
  7. July pruning tips: trees, shrubs, grapes, espalier

    July pruning tips: trees, shrubs, grapes, espalier
    Members of the Women's Land Army prune fruit trees in an orchard in the United Kingdom during the First World War. Trees and shrubs: keep pruning light this time of year, removing no more than ¼ of the live branches. Thin out water sprout wood before it gets very big, unless you are planning to do some grafting from...
  8. Choosing between fall and spring shipping

    Choosing between fall and spring shipping
    You have a choice, fall or spring shipment, but which is best? Even though many potted plants are available for fall shipping, these same plants are also available for shipment in the spring and you can order them now for either spring or fall shipment. Planting Trees and Shrubs Planting trees and shrubs can begin once the heat of summer...
  9. Do your homework now; Plan for your spring garden!

    Are you planning to put in an orchard next spring, or re-design your landscape with more edible plants? Robert Kouriks’ “Your Edible Landscape Naturally” will guide you through each step of the design process. A good starting point in landscape design is to make a drawing of your landscape, including the hard-scape (buildings, paths, other structures, or the drain field...
  10. It's Cider Making Time!

    It's Cider Making Time!
    Apples are an all-American success story-each of us eats more than 19 pounds of them annually. (Photo credit: Wikipedia) Here at Raintree Nursery we enjoy making apple cider each October. We use a Cider Press to extract the juice from the apples, ours is made by Correll. They are hand made and do have a waiting list. www.correllciderpresses.com Often...

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