Combating drought in the garden

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Mark McD
Title: Moderator
Joined: 2009-12-14
Combating drought in the garden

This year has been the "endless summer", day after day of hot sunny weather without rain, not even getting much in the way of thunderstorms. Once the soil reaches a certain level of dryness, where even trees and shrubs show the effects of drought, it becomes an uphill battle trying to resuscitate them by watering; a hose can barely begin to keep pace (and not to mention the water bans, restricted to watering every other day, which isn't too bad). The soil can become so hard, dry and dusty, that it reaches an "unwettable" state by actually repelling water.

Some plants cope just fine with the drought, others of course, do not. Has anyone used any techniques to help the more moisture sensitive plants stay hydrated? I was thinking about doing the following, I wonder if it would work or whether it would be a waste of time:

Take 2-liter soda bottles and cut off the bottom ends. Drill a few small holes in the caps, them screw them back on. Submerge a few open-ended bottles into the ground around water-sensitive plants (such as Kirengoshoma). Fill the bottle with coarse gravel, and cover with normal coarse-grade bark or stone mulch so that they're not visible. The idea is, after a watering "event" by hose, rain, or thunderstorm, the inverted open-ended bottles would collect water, and the reservoir of water could slowly trickle into the soil. The sheer fact the open-ended bottles would collect and redirect water downwards versus the inevitable run-off during brief downpours and the aforementioned unwettable soil states, I think could be an advantage.

Any other techniques?

Anne Spiegel
Title: Member
Joined: 2010-01-26

Mark, I've used coir in the mix for plants that want something closer to soil with some measure of success but it's not a complete answer by any means.  It just postpones the final death throes.  I also tried burying a plastic box filled with spaghnum moss (no holes in the bottom), a kind of minibog as a water reservoir.  Worked for a while for some white-flowering ranunculus. Since I'm not able to water at all, I grow as many dryland plants as I can (the Rockies, Turkey etc).  It takes experimenting to see which ones can also handle humidity. 

RickR
Title: Moderator
Joined: 2009-09-21

it would seem that almost the same effect could be done more simply by digging depressions in the soil surface, line with a permeable landscape cloth, or plastic with some holes, and fill with a coarse medium.

Rick Rodich    zone 4a.    Annual precipitation ~24 inches
near Minneapolis, Minnesota, USA

Lori S.
Title: Moderator
Joined: 2009-10-27

You have my sympathies, Mark.  
Perhaps to combat the runoff problem, it might help to make a small soil berm around some of the needier plants?  Water might then have a better chance of soaking in, rather than running off, whether from watering or from rain... ?  I suppose it might not be any more disruptive than the underground reservoir idea that you are thinking of.

Lori
Calgary, Alberta, Canada - Zone 3
-30 C to +30 C (rarely!); elevation ~1130m; annual precipitation ~40 cm

Hoy
Hoy's picture
Title: Member
Joined: 2009-12-15

What if you dig in such drainage pipes they use to drain moist soil but use both ends up?  All water you have you pour into it and the water will percolate into the soil. You can also cover the soil with a sheet of plastic that drains towards the ends of the pipe. Then all the water that fell here will reach the deeper layers of soil. You can of course cover the plastic sheet with gravel or something. The plastic sheet will reduce the evaporating too.

At my summerhouse we experience drought in May and June and the soil become like fat - expelling water. It takes months to moisten it throughout. I mix in sand to help absorb water.

Trond
Rogaland, Norway - with cool, often rainy summers  (29C max) and mild, often rainy winters (180 cm/year)!

Mark McD
Title: Moderator
Joined: 2009-12-14

Skulski wrote:

You have my sympathies, Mark.  
Perhaps to combat the runoff problem, it might help to make a small soil berm around some of the needier plants?  Water might then have a better chance of soaking in, rather than running off, whether from watering or from rain... ?  I suppose it might not be any more disruptive than the underground reservoir idea that you are thinking of.

I have tried, halfheartedly, making bermed rings around plants.  Since most of my property is sloped, the bermed rings tend to disappear over time, from natural settlement, runoff during large rain events, and when built-up around a young tree in my lawn areas, the tractor mower "blower hood" hits and flattens the raised areas.  There are times too, like in late winter and spring, when a bermed "dish" around a plant makes for too much moisture, and I tend to err on the side of better drainage.

It's just when one gets a prolonged drought, as we have this year, and with predictions that this will become more commonplace, that I must think harder about drought-proofing some of the more needy plants. 

Even some trees are now yellowing and shedding up to 50% of their leaves, many Magnolias, Halesia, my 20 year-old Katsura tree (Cercidiphyllum japonicum), most Hydrangeas look near death, etc.  Fortunately, at long last we had a thunderstorm this afternoon, and it poured for 30 minutes, hallelujah!  It helped bring the heat down from 92 F (33-34 C) to a more bearable lower steam heat. Now, if only I had some of those contrivances I threaten to make in place to redirect some of the runoff water into the ground.

And Trond, I am indeed doing as you suggest... after planting one area 5-6 years ago, a 2-3' high berm with unamended rocky-silty-clay soil, which becomes frustratingly "unwettable" as water just runs right off the dusty water-repellent surface layer, I now mix in coarse decomposed pine back mulch into any native soil before planting it.  I would use sand, but it's heavy and expensive to buy, so I'm going with coarse organics instead.  The older berm garden, mostly planted with Epimedium, is now scheduled for a makeover, to resolve the unwettable soil situation.

Mark McDonough
Massachusetts, USA, near the New Hampshire border USDA Zone 5
antennaria at aol.com
 

Fermi
Fermi's picture
Title: Member
Joined: 2010-03-03

Hi Mark,
"welcome to my world" is what I would've said before this winter when it would appear (touch wood!) that our 10 year drought has finally broken.
We've tried a lot of these startegies to combat the drought to keep things alive and green - not much would be relevant to you in your vastly different climatic zone. (Steering towards "drought hardy" and xeric plantings is our major change - so no more buying magnolias and rhodies which simply fry up in our garden!)
However the best advice we found for young trees is the use of a perforated pipe being placed down to the root zone, so that any water is directed there to encourage the roots downwards rather than up towards the surface. We've also found that planting in mounds or berms really helps which seems counter intuitive but it worked for a range of trees including Crataegus (Washington Thorn especially) and Koelreuteria paniculata the Golden Rain Tree. Mulch out to the "drip-line" is of course a great idea to get rid of competition from grass and weeds. Where we are the best mulch is coarse gravel or small rocks which can be taken right up to the trunk which you can't do with organic mulches such as straw.
The incorporation of organic matter into the soil is beneficial to improve the water-holding capacity but rain seems indispensible in the long run.
cheers
fermi

Fermi de Sousa,
Central Victoria, Australia
Min: -7C, Max: +40C

Mark McD
Title: Moderator
Joined: 2009-12-14

Thanks Fermi,  your comments derived from gardening in a climate that routinely deals with heat and drought, are useful indeed.  One of the difficulties here is, that unlike gardening in a dry US State where is a given that rainfall will be low for the year, New England can run the gamut of weather trends, with non-standard "freak" years of extreme weather... too wet or too dry.  So, it can be necessary to put initiatives in place to deal both with drought, and with extreme wet... depending on the year. 

Five years ago, or was it six, we had record wet spring, followed by an extraordinarily very wet June and early July, and even though I'm up on a hill and garden on strongly sloped ground, the water table was so saturated that it oozed water out of the hillside for many weeks.  Many of my raised beds are perpendicular to the downward slope, the seeping water saturated these beds from below, and I lost many bulbs (many alliums) from excessive moisture.  I now build my raised beds to be parallel to the downward slope, to not impede any seepage flow.

As I am writing this message, I just received an automated telephone call from Town officials, changing our every-other-day water ban to a 100% water ban with fines imposed for anyone caught watering.  Crap!  Looks like a stealth watering-can-only protocol might be in order, for only the most dire of thirsty plants.  Maybe when I go outside and work in the garden today, I'm start berming soil around those water-guzzlers.  Although, looking around the garden, I am really taking note of those plants that seem completely unfazed by lack of water, maybe I need to concentrate on those.

Regarding trees, I do what you suggest, I maintain a mulched "tree ring" around all my ornamental trees, about equal to the drip line... this really does help.  So far as Rhodies, I pretty much gave up on them when I first moved into my current location, just too hot, exposed, and dry on this hillside, but the Magnolias seems better able to cope... although mid to late summer drought can cause next year's flower buds to not develop properly.

Mark McDonough
Massachusetts, USA, near the New Hampshire border USDA Zone 5
antennaria at aol.com
 

Lori S.
Title: Moderator
Joined: 2009-10-27

Again, what a tough situation.
Just a thought... what do you have in the way of water-collection systems?  Given that you have an acreage, would installing a dugout (artificial and unattractive though they are, in their basic forms at least) be feasible/useful, in the longer run?  (That is, assuming that your water laws allow rain collection... it is a bizarre notion, where they do not.)

You are probably way beyond us on this front, and it is a much different scale, I know, but just to mention it, in case it is useful to someone... for our 1/3 acre city lot, we have 3- 150 gallon plastic stock-watering troughs for rain-gathering.  They sit in the utility area alongside the house, that is around the corner and thus not visible from the rest of the yard.  The eavestroughs from most of the house and garage funnel into these; one trough drains into the adjacent trough for drainage off the house, the other is independent and drains the garage roof.  Throw in a few goldfish for mosquito control, and it is great to have for watering in the greenhouse, and any spot watering and planting throughout the yard.

Lori
Calgary, Alberta, Canada - Zone 3
-30 C to +30 C (rarely!); elevation ~1130m; annual precipitation ~40 cm

Mark McD
Title: Moderator
Joined: 2009-12-14

The drought and hot weather continue, and now with a full 100% outdoor watering ban (with stiff fines imposed for anyone caught watering) I'm feeling desperate.  Need to make decisions about what can collapse yet still survive, and plants that will most likely perish in extended drought conditions, the later I will stealthily and with great thrift hand water :-X.  Two years ago, we had a drought period in late summer, where dozens upon dozens of Cimicifuga simplex atropurpurea where beginning to collapse, but I was able to water every other day, and most survived and flowered.  Some of those plants out of easy reach of the water hose, did dry up completely and collapse, and to my surprise, they leafed out next spring as if nothing had happened.

Last year, we were in the path of thunderstorm after thunderstorm, getting a good drenching many times, and well spaced out, and the magnificent spires of Cimicifuga simplex atropurpurea topped out at 8'; they were spectacular, and the burnt cotton-candy scent filled the air.  This year, even with hours upon hours of watering during the allowed every other day watering restriction, they were having a tough time.  Now, most flowering stems are crisp and frazzled and falling over; I wonder if I should just cut off the stems and foliage altogether, thus conserving their thickened caudex and root system to resprout next year.

Today there was a threat of a thunderstorm, some brief cloudiness, but no precipitation.  Drove down 1/2 mile to a farm stand to buy some corn, and the parking lot was full of big puddles, they got 10 minutes of rain!

I saved a couple of soda bottles to try and make some in-ground slow drip-irrigators, but my wife threw out the bottle caps.  So, after drinking up a bottle of Ginger Ale (a "soft drink" or soda pop to those not in the USA), I made a drip irrigator.  The holes drilled through the cap need to be very small and few.  I cut the bottom off the plastic bottle, then dug a hole and plunged it next to Leucosceptrum stellipilum (Japanese Shrub Mint), a wonderful fall-blooming member of the mint family that does a good impression of a Hydrangea in leaf.  The bottle was filled with gravel, plunged to slightly below ground level, and then covered with mulch.  In a rain event, or even with hand watering, hopefully the open-ended rain/water catchment device will redirect water to the thirsty plant (4 photos show this process today).  The last photo shows the plant earlier in the year, with attractive leaves.  It flowers in Sept-Oct... will show pics later if it flowers again, or else show photos from previous years.

Mark McDonough
Massachusetts, USA, near the New Hampshire border USDA Zone 5
antennaria at aol.com
 

Lori S.
Title: Moderator
Joined: 2009-10-27

Well done - it looks like that was accomplished with very little disturbance.

Off topic, but... Leucosceptrum stellipilum looks like quite an interesting thing to try - terrific if it would bloom early enough here to avoid being frozen off (and, as always, assuming hardiness, of course).

Lori
Calgary, Alberta, Canada - Zone 3
-30 C to +30 C (rarely!); elevation ~1130m; annual precipitation ~40 cm

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