Zone Pushing

Thom Morgan

By Thom Morgan, Springmoor Landscape Manager

On the US Plant Hardiness Zone Map, I am in zone 7b so plants that are hardy in zones 9 and above need special attention if I want to keep them.

Why do I go through the trouble?  I like collecting plants no one else has, and I enjoy the challenge of pushing my zone.

In the fall, usually the third week of October, I watch for reports of the first freeze and frost. Then I start grabbing shoots of Green, Bengal Tiger, and Siam banana plants. The parent Green and Bengal Tiger plants are way too big to move, but I can manage the shoots, by digging a twelve to eighteen inch root ball around them, and bundling them up in burlap. I can move all the Siam bananas because they only get six to eight feet tall.

However, I don’t want to loose the parent plants of the Green or Bengal Tiger banana plants either, so I put chicken wire cages around them and fill them three feet thick with pine straw as insulation.

In 2012, we didn’t have a winter, so to speak, so the bananas only died halfway back; they reached thirty feet that summer. Given another month, they would have flowered and developed bananas.

The winter of 2013 was cooler, and in 2014 we dipped into the single digits a couple of times. Both times the parent clumps of bananas died to the ground, so they had to start all over again from the shoots.

In mid-April, I brace myself for the yearly task of going under the house and bringing out all of my favorite semi-hardy tropical plants. Most are dried up piles of dirt, identified only by the ID tags I placed on them last October.

The first week of May, the parent clump of Bengal Tiger bananas I left out started sending up shoots.  After a few rains, I noticed shoots coming up from the Siam as well. I leave green elephant ear caladiums in the ground over winter – they seem pretty tough.

After I dig up the top priority bananas, I dig up the black elephant ear caladiums, which were thirty clumps last year. I noticed the green elephant ears coming up that I left outside in the ground, but the black elephant ears I stored under the house are still sleeping.

I did loose my beloved blue agave. It survived four winters of cold and damp because I planted it high in a sand and gravel mix. It was four feet wide, and three feet tall, with fantastic looking steel blue leaves. The winter of 2014 turned it to mush from the outside leaves to the center. Fortunately, of the plant’s twenty or so offspring I placed inside a poly house, eight made it. In mid-May, two shoots were coming up from where it once was, so it basically is coming back from the dead.

Thom's garden.

A lemon tree my daughter started from seed ten years ago goes in the garage, where it stays fifty degrees. Bromeliads, Dracena, Calamancia (a tropical citrus) and various cacti go in the garage as well.

I have noticed that everything does fairly well stored for the winter, but if something isn’t going to make it, it usually up and dies just about a week before it is warm enough to bring it out. I’m not sure what’s up with that.

Zone pushing is a lot of fun, but don’t get too disappointed if you loose a few beloved plants. Transplanting small, manageable off-shoots, storing bulbs, and insulating plants left outside is a lot of work, but it ensures you have back up plants in case there is another harsh winter. Here’s hoping we don’t have a winter like 2014 for a long time!

Other Plants for the Tropical Look

Musella lasiocarpa (Chinese yellow banana) looks more like a banana shrub than a tree, mine always die back, but return each spring, and gets huge yellow flowers.

Nerium oleander (Oleander) varieities have pink, red, or white flowers. My six-foot tall speciman turned brown over winter, and had to be cut half way back.

Butia capitata (Pindo palm)  hardy in zone 7b, my eight-foot-tall speciman did very well. All of the thirty or so seedlings I have turned brown, but show signs of sprouting new fronds at their tops.

Brugmansia sauveolens (Angels trumpet) varieties get huge yellow, peach, or white flowers. Mine all die back during the winter but send up new shoots each spring.

Springmoor Focal Points

Gardenia species  (August beauty), (Frost-proof), (Radicans), (Kleims

Hardy) gardenias will all be blooming on our campus in June.

Magnolia Jane (Jane magnolia) Bloomed in March, and have a second bloom in June.

Koelreuteria paniculata (Golden rain tree) Blooms with yellow chains of flowers from June to July.  The blooms eventually turn into orange lantern like pods in the fall.

June things to do

·       If you want tomatoes into the fall, now is the time to plant a second crop.

·       Eggplant, peppers, and okra like hot weather, so now is a good time to plant.

·       If you planted any garlic bulbs last August, now is the time to harvest- when the stems turn brown.

·       If you planted early spring crops like spinach, snow peas, and lettuce, they should all be spent now. Add compost, and till soil.  Allow area to lay fallow until August.

·       Any carrots planted in early spring will be ready to harvest now.

·       Pruning, if you have to prune azaleas now is a good time after blooms have faded.

Books for this Month: “Beneficial birds in the Garden” by Bob White

“Protecting your trees in a Storm” by Gail Winds