Wednesday, November 24, 2010


Well, in case you didn't notice, it seems as though winter is here to stay! We had a wet heavy snow move through on the 13th that caused quite a bit of damage to some mature trees around campus. We filled 5 or 6 dump trucks full of debris to be hauled away to compost. We also had our cities forestry crew come in to take care of broken and damaged branches that we could not reach up in the canopy of many trees. A lot of the branches were buried by the icy heavy snow, and will have to be cleaned up in the spring once all of the snow melts.

In addition to storm cleanup, our outside crew is putting some final touches on grounds before they leave for the winter. One easy way to spruce up a somewhat dismal landscape is to put out some winter display containers. Using only materials found on grounds (most from that storm damage), and using cut-back perennial materials, we have put together some pots in front of our office building on the zoo. We used cuttings from evergreens including white pine, Chamaecyparis, and a Douglas Fir with interesting pine cones. We also used cuttings of red-twigged dogwood, miscanthus flame grass (silver plumes), and chasmanthium (oat-like seed heads). Using all of this material, we arranged the cuttings in a pot of soil, and then watered it in. These plants are no longer alive, and don't need water, but the cold temperatures will cause all of that water to freeze, and hold everything right in its place. The best part about these displays are that they are free! You might not have all of these materials in your yard, but think about what you do have. Any everygreen branches will provide color and structure all winter. Grasses add a flowing look, and many hold up all winter long. Colorful branches, such as the dogwoods are a great added touch. Also, any plant with berries adds that extra pop (if the birds don't eat them all!). You can also find some interesting curly willow, or branches with a unique form and structure to add interest. Hopefully this will inspire some of you to try out a beautiful winter display of your own!

Tuesday, November 9, 2010

What's happening with hydrangeas?

This week horticulture staff are begining to remove all the leaves from next spring's hydrangea crop. You may be wondering why we would remove all the leaves from perfectly healthy plants. Hydrangea plants need to undergo a dormancy in order to flower. Outside, they would go dormant in the winter when temperatures drop. In the greenhouse we have to fake that seasonal change. When they go into dormancy, hydrangeas lose most of their leaves, so taking them off ahead of time reduces the mess later. Not doing so could result in old, dead leaves accumulating and harboring disease.

Hydrangeas are a major feature of the Conservatory's Spring Flower Show and require nearly 10 months of care before they go on display. The conservatory starts all of our hydrangeas from unrooted cuttings we receive in the middle of June. We grow them up through the summer and let them set buds before providing the dormancy the will need to flower. The hydrangeas will be dormant in a cold area of the greenhouse for approximately eight weeks. Then they are moved to a warmer spot where they can begin actively growing again and flowering. Horticulture staff use specially timed "feedings" of ammonium sulfate to ensure the development of blue flowers. This year we are growing mostly a variety called 'Oregon Pride.' This is a variety we have used successfully in past years. We are also experimenting with eight new varieties to see if they perform as well (or better!) than our traditional selections. Look for these hydrangeas in the Sunken Garden next spring.

Wednesday, November 3, 2010

Planning Annuals

This is the time of year for raking leaves, cleaning up garden beds, and believe it or not, planning and ordering our plants for next year. Right now our outside gardening staff is hard at work, planning, designing planters and beds, and picking out fun and exciting plants for next years displays. We aquire many different catalogs from various growers and suppliers around the country, which is where we get ideas for great combinations and new varieties that have been released.

Some of the areas that we plan for include: the double sidewalk in front of the visitors center, the Skipper and Enchanted butterfly gardens, and various container plantings all over conservatory and zoo garden areas. Along with planning for our areas, we also grow plants for other gardens in the city, inluding some of the City of St. Paul golf courses. For those areas we grow about 75 flats of plants, and about 100 4-1/2" plant material. We probably grow about 2.5 times that number for our gardens alone.

We then put together a large list of plants to order, and then our indoor staff recieves shipments throughout the winter and spring. They then take care of planting the seeds. Sometimes we also get plugs of plants, which then need to be transplanted into larger containers. By careful timing with seeding, and different greenhouse conditions, the plants are all rooted in and ready to be planted in the ground or a container in the spring!