Growing Things: Plagued by weeds and galls

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Q I believe my 16-year-old rocket junipers are infected with Hawthorn rust. For about three years I’ve cut off the spore balls I come across and cleaned off the orange gobs that form after rain. This year, one of the trees was dead. I’m told my trees need to be treated by a herbicide but I cannot find the name of any herbicide to use or where one can buy some. I’ve looked at the websites of arborists in Edmonton but cannot find any that offer to treat the problem. Therefore, I hope you can provide me some direction. 

A The problem you are describing is a fungus called juniper Hawthorn rust, which is closely related to apple cedar rust. On evergreen hosts, such as the junipers, you’ll see the formation of galls that look like brown apples. When mature they send out these bizarre looking, gelatinous, orange fingers that you’ve described. On deciduous hosts, the leaves will begin to show yellow spots. Over time these spots will turn orange and eventually develop black spots. By mid-summer you can see tiny tubes forming on the undersurface of the leaves.

Once infected there is no treatment for the current season. Pruning out the growth is the most effective way to reduce infection. Disinfect pruners between cuts with a solution of one litre of water and two tablespoons of bleach. No chemical treatment is completely effective. I have read anecdotal evidence of using garden sulphur spray as a preventative measure. Start spraying in the spring when the buds begin to form and swell, again after the buds open and once more about 10 days after open. If you’re already seeing the orange blobs then sprinkling sulphur powder or spray on the surrounding leaves may act as a preventative.

Weeds of ages

Q About three years ago the city did sidewalk upgrades and removed grass from both the boulevard and approximately one metre of grass from my lawn and replaced it with sod. Long story short, the sod needed replacing the following year and now is producing weeds that have not seen the light of day since the Jurassic Period. But no grass to speak of. I reseeded my lawn the last two years and again this year and have a decent lawn now, but what do you suggest for the boulevard? Should I purchase a tank of Round-Up and spray the boulevard to kill the weeds? Should I do this just before winter and let the soil rest and then reseed in spring? I’m not looking to produce a showcase lawn on the boulevard, this is city land and although I’m responsible to maintain it, I’m not prepared to make it my life’s work. I would appreciate any advice you could give.

A I’m still laughing at weeds from the Jurassic. Since this is city property, it may be worth a phone call to let them know you’re concerned about the weeds in this area and ask if they’re prepared to do something about it. If they say you have permission to do the remediation, I would not recommend using Round-Up. Since I don’t know how big an area we’re talking about, if it’s a workable size, I’d use heavy-duty black landscape plastic laid down on top of the weeds for a season. This will kill the weeds and then you can come in next year and work the soil and reseed. Once reseeded you may have to monitor for weeds that have germinated from any seeds left behind after the plastic treatment.

Learn more by emailing your questions to filipskigerald@gmail.com, reading past columns in the Life section at edmontonjournal.com or my book Just Ask Jerry. You can also follow me on Twitter @justaskjerry01.