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BRUNERA 'jack frost' macrophylla affected by oak tree?

Posted by grandma_gardener_02 5 (My Page) on
Sat, Jul 19, 14 at 19:11

We have had some beautiful 'jack frost' macrophylla [your website would not let me enter the common name - BRUNERA - unless I capitalized it] under a very tall oak tree for about 5 years. This last winter didn't help, but it now seems that they have lost their vibrancy - plants not bushing out, small leaves, didn't flower well. Could this be due to some chemical that the oak has put into the soil? I know oak leaves are not good to let accumulate, but we keep the base of the tree totally free of leaves. We have kept branches cut so that the light environment pretty much has stayed the same. Also, have felt like the watering schedule has stayed the same. Any ideas?

Follow-Up Postings:

RE: BRUNERA 'jack frost' macrophylla affected by oak tree?

I find Brunnera macrophylla 'Jack Frost' to be very long lived and have numbers of plants up to ten or more years old.

It is nowhere near as vigorous as the species, which is also quite a seeder.

As they say, Brunnera does like moist, well-drained, rich soil with lots of organic matter.

Perhaps in that location the soil is now exhausted.

RE: BRUNERA 'jack frost' macrophylla affected by oak tree?

  • Posted by mxk3 z5b/6 MI (My Page) on
    Sun, Jul 20, 14 at 13:01

It's probably due to the fact it's under a tree, the soil is probably too dry, due to the tree taking much of the moisture combined with the fact it's under the drip line (I'm assuming). Brunnera (all of them, not just Jack Frost) prefer moist soil, they perform quite poorly in drier conditions.

If you really want brunnera in this location, I would suggest digging up and re-planting in a spin-out bag or digging a large hole, lining with plastic (with bottom cut out or large holes for drainage), filling with top-quality soil and replanting. Or, you could use moisture-absorbing crystals (e.g. SoilMoist) mixed into a large, freshly amended planting hole to help get the root system well-established and better able to withstand some dryness. I've used these tricks in the past, and they do work, but it is imperative you offer supplemental moisture if the plants are under the drip line.

RE: BRUNERA 'jack frost' macrophylla affected by oak tree?

These are the most pitiful plants I've ever tried to grow. They can't take the heat here. I'm trying a new one called 'Sea Heart' that seems to be doing much better.

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