African Garden + weather woes

Preparing for the Worst-case Scenario
the back lawn of Squirrelhaven, June 26, 2012

What, me worry? You'd better believe I'm worried about the gardener's worst nightmare, drought. Extreme cold in our Midwestern gardens isn't a big cause for concern, especially if there is good snow cover. In the worst case, you might lose a couple of plants. By contrast, with a drought, you might lose everything.
Now I'm a firm believer in not worrying. Worrying doesn't solve anything, it doesn't prevent the worst from happening, and it sure doesn't make you feel any better about it. In fact, should the worst come to pass, worry renders you even less able to deal with the situation. So, what is a gardener to do, but relax and, as a first step, assess. For a second step, plan.
Why am I worried about the worst-case scenario of drought? According to NOAA, as of June 19, Northern Illinois is in a state of "abnormally dry" conditions (the next step up is "moderate drought"), and there was a wildfire at the forest preserve here yesterday. (As of today, Tom Skilling, WGN meteorologist calls it a "drought.") But I've been getting that deja vú feeling for the past couple of weeks. Memories of 1988 have begun to resurface. If you were in Chicago or Northern Illinois in 1988, you know what I mean. It started late in May, the feeling of an oncoming hot, dry summer. 1988 has become the benchmark for me for heat and drought. But I can't recall ever seeing brown, crunchy lawns in June.
A bit of trawling through the weather statistics has revealed that the summer of 1988 wasn't as dry as 2005 or 1991, the driest summer in my lifetime. (I was living here at Squirrelhaven by then, but I had just started to put in the garden and I didn't start keeping a garden journal until 1996). I can't recall any watering restrictions in 1991, but in 2005, some suburbs were beginning to impose them. Unlike many suburbs, my town doesn't get its water from Lake Michigan. In 2005, there was fear that the wells here would run dry, so the town banned all watering with very limited exceptions. I lost several woody plants and some perennials that year. 2005 was the last time there was a summer-long drought here.
May rainfall this year was less than that in 1991 but more than in 2005, and the.44" of rain in June so far is behind the.95" total for June 1991 and the.76" of 2005 (weather statistics from Weather Warehouse), and there's only a 30% chance of rain in the forecast for my part of Chicagoland for the next four days. The two-week forecast is dismal, and the long-range forecast is uncertain, but from the way things are going, a drought appears likely for the Chicago area. There will be watering restrictions.
To avoid simply worrying about what will happen, it's better to have a plan, in this case, a watering plan. It is better to water less frequently for a longer time than more frequent, shallower waterings, so decisions must be made, before watering, what will be watered during a given opportunity. There simply isn't enough time to water everything as often as one would like. Having a plan in hand will make these watering decisions easier.
First, determine which plants you could least afford to lose, those that are irreplaceable and those that would require a long time for replacements to reach the same state of maturity.

I would hate to lose this Abies koreana 'Lippetal'

Here at Squirrelhaven, those plants are Abies koreana 'Lippetal', Actaea 'Black Negligee', Actaea 'James Compton', Aquilegia vulgaris 'Sunburst Ruby', Calycanthus floridus 'Athens', Cercis canadensis (redbud), Cornus alternifolia 'Stackman' (Golden Shadows™), Cornus kousa 'Beni-fuji', Cornus 'Aurora', Cladrastis kentukea (yellowwood tree), Daphne x burkwoodii 'Silver Edge', Heptacodium miconiodes, Hosta 'Saketini', Heuchera 'Havana', Paeonia suffruticosa 'Ofjuinishiki' (tree peony), Quercus x bebbiana, Sanguinaria canadensis 'Multiplex', Thalictrum thalictroides (a/k/a Anemonella thalictroides) 'Oscar Shoaf', Thuja occidentalis. Ordinarily, I wouldn't include Asclepias pururascens and Liatris aspera on that list, but those plants are part of the Native Seed Gardeners program, and I can't afford to let them die.
Next, determine which of these needs watering the least. The Anemonella and the Sanguinaria become ephemeral in dry conditions, so they are less likely to die from drought. Hostas are remarkably drought resistant, but 'Saketini' is a mini and planted just this year, so I'd better keep an eye on it. If any of the plants listed are xeric tolerant, such as the Liatris, they also should be excluded. What remains are the highest priority plants.
Next, list all the plants that were planted recently, meaning from last fall to now. These plants need more coddling than well-established plants if they are to survive.
Now, consider the conditions in which each of these plants are growing. Those in more shade and moisture-retentive soil are of less priority than those growing in full sun and more well-drained soil. With these priorities in mind, draw up a watering schedule. The most imperiled plants, those that are the least drought tolerant, growing in full sun and well-draining soil, should appear more often on the schedule.
For woody plants, water for three hours using a soaker hose or the soaker setting on a hose end sprayer. For perennials, hand water with a watering can, saturating the area around the plant. It may take more than one watering-can full. Once a week should be sufficient for most plants.

Ahhh, I feel better already.

This plan is for ornamental plants only. You must decide for yourself whether your edible or container gardens are a priority. If they are, apply the same logic, but the watering frequency needs to be adjusted as the ornamental plan is to ensure survival, not beauty or productivity.