Question
QUESTION: We noticed last year our large 20 ft high Star Magnolia was loosing leaves, branch by branch . Turning brown and dropping off. By the end of fall 3/4 of the tree was bare. This spring only one branch flowered and "tried" to put out a few tiny leaves. We believe, after researching, that it may have died of Wilt.
We would like to replace it and was wondering if we could put in a Cornus Kousa, Korean or Chinese Dogwood, in its spot?? IF it was the Wilt do you think this type of tree would be resistant to it? We want something small, and multi-branched to replace it with.
We live in Zone 5b, on the SW side of Chicago.
I understand this type of tree is hardy and not susceptible to the diseases that the American Dogwood is. It will be on the east side of our home, in full sun.
We are also thinking of a Redbud. What would you suggest?
Thank you...
Sue

ANSWER: Sue:

The dogwood is a good tree.  In nature, the dogwood thrives in the shade of other trees.  If you want to put a dogwood in full sun, be sure that the tree you purchase has been grown in full sun. These trees need a well drained soil and are typically shallow rooted, so be sure to avoid them getting too dry during the windy-hot days of summer.  Mulch around them (no more than 3" deep)to conserve soil moisture.  Be sure to pull the mulch back away from the trunk an inch or 2 so as not to allow mulch to pile up against the trunk.  Piled up mulch will invite insect problems. Also, if you select dogwood, be sure it was grown in your zone, otherwise flowering and overall vigor may be compromised.

Good soil drainage is helpful in reducing the chances of wilt on any plant.  Most of the common wilt disease prefer extended wet soil conditions.

The redbud would be a good choice also.  Of the two, I would favor the redbud.  Again, good soil drainage is important.  The mulch is good for any tree.  It also keeps the string trimmers and lawnmowers away from the tree.  It takes about 0.006 seconds for a stringtrimmer to kill a tree by damaging the protective bark near the base.

P.S. My wife and I are planning a trip to Chicago in July or August.  It will be my second time there and my wifes' 4th or 5th.  I like the aquarium. She loves it there!!

Regards
Steve

---------- FOLLOW-UP ----------


Shedd Aquarium   QUESTION: One other thought...you mentioned mulch, which we have always had around the base of this tree. It sits in a large island covered with mulch, to about 3 " deep. Could we have brought in the mulch in a new load of mulch we put down last year? Does the virus live on the wood of chipped trees and thus contaminate the area with it??
Drainage has always been good in this area and our season last year was not over all wet. How can I prevent this from happening again? Any type of spray I can use??

PS You have great taste when visiting Chicago. ;-) We have a awesome city, full of great things to see and do. The Aquarium is one of my favorites also. And a fun place is Navy Pier. Not to mention the Art Institute too. Don't forget shopping on Michigan Ave...

Answer
Sue:

Most of the wilt diseases in trees are caused by fungal organisms, not viruses.  There are a few that are caused by bacteria.  It is possible that some of these organisms could come in on mulch, but VERY VERY remote.  (I learned a long time ago to never say never)   So, you are probably quite safe with the mulch.  Most root rots are aggravated by prolonged wet soils.  These groups of microorganisms can live easily in the soil, but are more likely to attack a plant that gets stressed out by sitting in wet/poorly drained soils.  Many of the wilt causing organisms can also live in the soil for extended periods (years)and again attack stressed plants too.  Growing resistant plants is the best way to avoid many of these infectious diseases, unfortunately resistance isn't always available in our landscape plants.  Prevention is best.  Good fertility and watering can help a lot by promoting a vigorously growing plant.

P.S. Thanks for the photo. Takes me back to about a year ago. Noticed the sign on the building.  I love jellies!!  Yes, my wife enjoys your city and my daughter wants to move there!!

Steve