CVHS Forum Partners with Vancouver Island Master Gardeners

Q & A
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We are delighted to announce that the Vancouver Island Master Gardeners Association (VIMGA) has partnered with us to bring their professional gardening advice to our members through our gardening Forum.

Any time a member asks a question on our Forum, it will automatically be forwarded to the Garden Advice Line at Milner Gardens and Woodland (in Qualicum Beach) and a team of Master Gardeners will work together on the response which should be completed within a few days (of course, we hope that our members will continue to provide their excellent advice as well!)

This collaboration will also benefit the VIMGA by providing its members with more opportunities to fulfill their yearly advice hour requirements to keep current.

So, while we are indoors more, and in our gardens less, now is a great time to form and ask those important gardening questions!

Here is a question that was asked on our Forum recently and forwarded to VIMGA—this is the question:

Question:

Looking for suggestions on what type of tree to plant in a BIG old tree stump.

  • The cavity in the stump is 3’ x 3’ square, 2.5’ - 3’ deep.
  • The stump itself is 6’ tall and 5’’ wide.
  • There are drain holes drilled in the cavity.
  • The exposure is full sun.
  • The tree will get regular hand watering until established and as necessary afterwards.
  • Prefer something with a weeping canopy or at least a large canopy. Crimson maple?
  • Thinking about 10’ - 12’ in height for scale.

Answer:

While it is possible to plant a new tree into a stump, it is generally recommended to find a new planting site for any new tree, ideally 6 - 8 ft away. At minimum, ensure an adequate amount of time has passed to allow for the roots of the old tree to decompose and the ground to settle.

Here are some additional things to consider in advance:

  • As decomposition of the old tree material can be a breeding ground for pests, it is important to look for signs of harmful pests like termites before planting another tree in that location. As well, look for any signs of decay or fungal infection. If the prior tree was killed due to a disease, make sure to plant a tree that will not be affected by that disease.
  • Depending on the age of the stump, the ground may not have settled yet. As the new tree grows, the weight of it can cause it to sink, and the root flair may end up below the surface (ideally the tree root flare should be at surface level).
  • Ground woodchips left in the area beneath and around the stump can deplete the soil of nitrogen. Testing the soil for its nutrient composition is key to identify any required amendments, as well as selecting a tree.
  • A stump with tall “walls” may lead to water collection, and moist, soggy conditions, which may not be suitable for some trees. Ensure the area within the stump is adequately draining through the cavity.
  • There may be excessive air pockets in the soil beneath the stump from roots of the old tree decaying. Alternatively, if roots have not decomposed (depends on the age of the stump), there could be inadequate space for the roots of the new tree. Grind out the bottom area of the stump 6 - 12 inches below the surface (ensuring to remove any remaining root mass) and refill, making sure to firm and water the new soil down well so that the new roots have direct contact with the soil.

Unlike most maple trees which prefer dappled shade, the crimson series you mentioned is one of the varieties that can tolerate full sun. You may still need to protect them from full sun when they are young, however. The 6’ height of the stump may help with this.

They are also not drought tolerant, and regular/deep watering during particularly hot periods is critical. They have a hardiness zone of 3b-7, so it is important to check your zone as areas on Vancouver Island reach zone 8. Finally, a crimson maple may exceed your desired height range - they can grow to 35 - 40 ft.

Trees 10 - 12 feet in height are usually considered “dwarf”, or small. Here are some trees in that height range that prefer full sun, and can grow on Vancouver Island:

Here is a database you can use to generate additional options by entering height, spread, zone, and light requirement criteria: Plant Database Search - Okanagan Xeriscape Association

This one from Gardenworks is also helpful (please note that choosing full sun will result in options that include “partial shade to full sun”, you may want to exclude those options): GardenWorks Plant Database - Vancouver Victoria Burnaby Penticton Coquitlam British Columbia BC.

Thanks, Karen & Veronica

Sources:

https://web.extension.illinois.edu/askextension/thisQuestion.cfm?ThreadID=15340&catID=199&AskSiteID=87

https://www.rhs.org.uk/plants/types/trees/stump-removal

Vancouver Island Master Gardeners Association

Phone: 250-752-0312
Email: GardeningAdvice.MilnerGardens@shaw.ca
Web: Gardening Advice | Milner Gardens | Vancouver Island University | Canada

Milner Gardens & Woodland’s Gardening Advice is offered through a partnership between Vancouver Island University’s Milner Gardens & Woodland and the Vancouver Island Master Gardeners Association.

Advice is given without charge and although it is believed to be correct, it is given on the basis that there is no liability on the part of the Master Gardener, VIU, or the Vancouver Island Master Gardeners Association.

Many thanks to the Vancouver Island Master Gardeners for providing the following response through their partnership with the Garden Advice Line at Milner Gardens and Woodland.

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