2003 Annual and Perennial Trial Results

Magnolias in Minnesota?  Eight years ago, we began experimenting with container-grown magnolia liners to space out in our fields for B&B production.  We wanted to produce multi-stem plants, so we started with Royal Star and Merrill magnolias, expecting Royal Star to be hardier.  Royal Star turned out to be marginally hardy in our fields and significantly slower to make up to B&B sizes.  Merrill is much more reliable for us, making up beautifully from a #2 (15-18” tall) liner to 6’ or 7’ in four years.  Magnolias grow well in container culture also.     
Merrill magnolia has an upright oval shape when young, with a dense mass of ascending branches, highlighted by large fuzzy flower buds in winter.  Three-inch white flowers cover the plant in late April, just prior to the emergence of leaves.  Merrill’s bloom is always impressive, set against the bare branches of all our trees, but it is also an indicator that we had better getter get the rest of our B&B digging finished, and soon.   
Leaves emerge bronzy-green and mature to deep green.  No foliar disease problems have been noted, but Merrill magnolia is susceptible to Verticillium wilt, as are all magnolias and many other genera.  Merrill is quite adaptable to acid or calcareous soils, but care should be taken to keep plants evenly moist through use of mulch and proper siting.  Mature size is between 20 and 30 feet in height and about as wide.  An excellent 20-year-ld 20-foot tall specimen is located just left of the office entrance at Bachman’s Nursery Wholesale Center in Lakeville. 
Trees in our fields are most susceptible to winter damage during their first winter after planting, and Merrill is no exception.  During the cold dry winter of ’02-’03, we saw some dieback in our youngest Merrill magnolias, but certainly no more than in river birch or hackberry.
Our nursery is located above Lock and Dam #2 on the bluffs of the Mississippi, and the wind really howls during our winters.  We are not set up to grow varieties that require special microclimates or winter protection.  We have tried and rejected varieties like Autumn Blaze Pear, Norwegian Sunset Maple and Brandywine Crab, due to marginal winter hardiness.  Cucumber magnolia (M. acuminata), Royal Star magnolia (M. stellata ‘Royal Star’) and Leonard Messel magnolia (M. x loebneri ‘Leonard Messel’) fall into this same category  for us, requiring careful siting or winter protection to succeed in the nursery.  Merrill magnolia presents no such problems and has become a valuable addition to our inventory.

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