Monday, January 30, 2012

A Half Zone

The Chicago area is now officially a half-zone warmer. The U.S.D.A.’s new Plant Hardiness Zone Map, issued last week, puts the city of Chicago in zone 6a and most suburbs in zone 5b.

You might want to think twice before you start celebrating, however.

Yes, the map is more detailed and accurate than the 1990 version. And the USDA’s Website now has an interactive version. Just enter your zip code and it will tell you your zone. That’s especially handy for new gardeners, who can use it to choose plants appropriate for their area.

Like any map, though, it has its limitations. The long-awaited changes are only based on the average lowest winter temperatures. As the USDA press release noted, the zone designation “does not reflect the coldest it has ever been or ever will be at a specific location.”

In other words, if there's a very cold winter, you are still likely to lose some plants. And as any one who has gardened in the Chicago area knows, our winters can be extremely volatile. Witness this year’s light snowfall and mild termperatures, a major contrast from just a year ago.

The map’s changes are a bit dated as well. It’s based on 30 years of data ending in 2005. That means the most recent temperatures included are six years old. The previous map, released in 1990, was based on 13 years ending in 1986. (See this article by Tony Avent of Plant Delights Nursery, who was involved in the map-making process, for a description of the latest effort. For his history of U.S. hardiness maps, click here.)

Cold temperatures probably aren’t even the biggest limiting factor for Chicago area gardeners. It’s the heavy clay soil, which makes it difficult to grow plants that need good drainage or prefer acidic soil.

For example, I’d love to grow pieris japonica, also called lily-of-the-valley shrub, because of its fragrance. I’ve tried several times, though, and failed. Rhododendrons and azaleas also are difficult to grow for the same reason.

That said, area gardeners can feel slightly more comfortable “pushing" the zone – trying zone 6 plants in a 5b garden – now that the new map has been issued. I think most experienced gardeners already do this, using the “micro-climates” or more protected areas of their garden to try marginal plants.

So I’ll half-heartedly take another half-zone. But I'm not planning to throw out my winter coat any time soon.

By Karen Geisler

Tuesday, January 24, 2012

Tillandsia -- Out of Thin Air

T. bulbosa belize
They looked like something straight out of the movie Avatar, with their colored leaves and strange flowers. And after the first snowfall this winter, they promised to provide a welcome touch of the tropics.

So I decided to try air plants, or tillandsias, again. I had killed the first ones I bought several years ago so this time around I did a little more research. Turns out they have a fascinating background.

Tillandsias originally were thought to be related to mistletoe as both grow on trees. Air plants, however, aren’t parasites the way mistletoe is. Their roots are only used to anchor the plant. They pull their moisture and nutrients from the air through their leaves, not the host.

They actually belong to the bromeliad, or pineapple, family. The name covers more than 500 different species, mostly in Central and South America. It includes the Spanish moss that hangs on trees in the southern U.S.

T. ionantha van hyningii
The category or genus was established in 1753 by Sweden’s Carl Linnaeus, who set up the current system of botanic nomenclature.

It honors Finnish botanist Elias Tillands (1640-1693) who got so seasick going the eight miles by boat from Sweden to Finland that he traveled 200 miles by land on the way back. Not surprisingly, Linnaeus chose a plant that can not bear to stay wet.

Air plants do need moisture, of course. They just don’t need roots to do it. In fact, putting an air plant in soil is a sure fire way to kill it.
On the other hand, misting alone isn't enough. That's what I had done the first time and unfortunately it's still recommended by several Websites. These plants need to be immersed in water, shaken to remove any excess water and then allowed to dry thoroughly.

Exactly how often they need a drink and how long seems to be (excuse the pun) up in the air.

Some sites say once a week is sufficient while others say two or three times. Some recommend you only dunk it for a short while. Others specify an hour or even longer, especially if you’re going on vacation or the plant looks particularly dehydrated.

It seems to depend on the exact variety of air plant you have, with some varieties needing more than others. Guess that makes sense. The same goes for plants in my garden, at least when there isn’t five inches of snow on the ground.

There is agreement that air plants need lots of bright indirect light. So I’m putting them on a table next to a window that opens onto my westward-facing porch. I'm still looking for some way to supplement the paltry sunlight available this time of year.

T. aeranthos clavelles

Other than that, care seems to be pretty easy. Avoid distilled water. Fertilize once a month using either a special bromeliad mixture or an orchid fertilizer at one-quarter strength.

I’m planning to try various ways of displaying my new air plants. For now, they are in some very small pots, with their leaves suspending them in midair. It still seems strange having plants with no visible means of support, that can get what they need out of thin air to produce such beautiful blooms.

There is one sad note – the flowers mean these plants are in their final stages of life. I’m hoping they will produce babies or “pups” at their base before they die. Those plants should then mature and produce "pups" of their own. Sort of a “circle of life” thing. Not unlike Avatar. Or was that another movie?

By Karen Geisler

Wednesday, January 11, 2012

Organizing the garden

My collection of plant tags
I started out with the best of intentions. All I wanted to do is organize my gardening information in one place. Now, I’m back where I started.

For the past five years, I’ve been saving every plant tag, receipt and invoice with plans to eventually set up a spreadsheet or start a garden journal. That has never happened though. Just too many plants, too little time.

With the New Year, though, I resolved to make a fresh start. I would take my bulging file folder with all that information and turn it into something useful. Surely there was a ready-made solution out there for me. I checked out several possibilities: bound journals, three-ring binder systems, computer software and on-line garden tracking services.

None of these turned out to be exactly what I wanted. Most were strong in some areas but weak in others. Many were pricey and/or not that user friendly. And the idea of spending even more time at the computer keyboard than I already do just wasn’t that appealing.

I'm a bit discouraged but a garden organizer still sounds like a good winter project. How else can I track which plants I have in my garden, especially when those baby bunnies nibble on my perennial geraniums? (Let's see. Was that a Rozanne or Johnson’s Blue?)

I’d also like to track bloom times, bulb locations, fertilization, pruning, pests and soil analysis/amendments. A “to do” list and a plant “wish list” would be nice as well.

So I’m now in the process of using Microsoft Word and Excel to create pages like those I found online.

If you're interested, check out the garden journal templates at and Hobby Farm. Other templates on the Web include Homestead Garden, Gardening Quick n Easy and Northern Gardening. The University of Illinois Extension has an especially nice garden journal page for kids. If you're a seed starter or vegetable gardener, there's Arbico Organics and Blue Boardwalk.

Wish me luck. If I get really ambitious, I may splurge on a customized three-ring binder. It all depends on how far I get before the first plants emerge this spring.

After that, all bets are off.

By Karen Geisler