Theresa Knutsen

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

  1. Mychorrizal fungi in your soil!

    Mychorrizal fungi in your soil!
    turned soil (Photo credit: willismonroe) If your soil has been recently disturbed, is low in organic matter, or is imported, your fruit trees will also benefit from the addition of mychorrizal fungi at planting time, #T185 Myco Paks. The fungal organisms in these packets are normally found in association with the root systems of healthy deciduous trees and some...
  2. After winter storms, check your trees for damage

    After winter storms, check your trees for damage
    Two apple trees, coated in ice following an ice storm, with the sun shining bright in the afternoon sky. (Photo credit: Wikipedia) After winter storms, inspect trees and bushes for damage. Make clean cuts where there are ragged tears and breaks to minimize fungal infection opportunity. Prop fallen trees back up, if the root system has not been damaged...
  3. Grafting in the Winter

    Grafting in the Winter
    English: Photo of a recently grafted cherry root stock and scion (Photo credit: Wikipedia) If you are planning to do some grafting this winter or next spring, December –February is the time to collect scion wood, from fully dormant trees. You need the previous seasons’ healthy vegetative growth for the scion (the shoot you cut from a desired variety...
  4. FAQs: When should I expect to harvest the first fruit from my new fruit tree/berries?

    FAQs: When should I expect to harvest the first fruit from my new fruit tree/berries?
    English: Fruit on display at La Boqueria market in Barcelona. (Photo credit: Wikipedia) When should I expect to harvest the first fruit from my new fruit tree? Our standard answer is 2-3 years to first fruit. In some cases your trees may arrive with flower buds and be apparently ready to produce fruit. It is best, however, to remove...
  5. Taking care of container plants in December

    Taking care of container plants in December
    Unripe Meyer lemon, Citrus × meyeri. (Photo credit: Wikipedia) Finally, the lemons on your Meyer’s Lemon Tree that set last February are starting to swell and look like they will really ripen (next month)! Continue monitoring for insect populations, early detection and treatment will keep those pests under control. Keep your lemon trees flowering and fruiting periodically throughout the...
  6. Peach leaf curl control

    Peach leaf curl control
    English: Peach leaf curl by Taphrina deformans (from Professional Institute of Agriculture and Environment "Cettolini" Villacidro, Italy) Italiano: Bolla del pesco causata da Taphrina deformans (Photo credit: Wikipedia) One of the more significant fungal diseases in the Pacific Northwest on peaches is Peach Leaf Curl. Once the chill requirement for the peach tree has been met, the sealed bud...
  7. Pruning in December

    Pruning in December
    Pruning shears. (Photo credit: Wikipedia) Once your trees, shrubs, and vines have achieved full dormancy (leaves on the ground for deciduous plants, no tender new growth buds visible on evergreen plants) you can begin dormant season pruning. If you tend to experience a lot of freeze, wind, or fungal damage during the more severe part of winter it might...
  8. Planning ahead for spring

    Planning ahead for spring
    Planned backyard garden (Photo credit: renoir_girl) Are you planning to put in more trees or shrubs next spring? If you know what trees and shrubs you want, and where they will be planted, you can prepare the planting holes for them now. Make a plan of where you will plant your new trees, and mark the locations in your...
  9. Don't over-water plants but don't forget them

    Don't over-water plants but don't forget them
    English: A collection of watering cans of assorted sizes. (Photo credit: Wikipedia) Be careful not to over-water plants in the greenhouse or indoors as their growth slows down with shorter and cooler days. Water thoroughly, then allow most plants to dry out before watering again. Provide humidity for citrus and other sub-tropical plants growing indoors. Outside, most locations will...
  10. Avoid pruning if possible; cut back your blackberries and raspberries

    Avoid pruning if possible; cut back your blackberries and raspberries
    Avoid fruit tree pruning, except broken or dead limbs, if trees or shrubs are not fully dormant or approaching dormancy. Open wounds heal more slowly as trees are approaching dormancy, increasing the opportunity for fungal infections to occur. If you have not yet done so, cut out old dead fruited canes from blackberries, raspberries, and related hybrids after fruiting and...

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