Give soggy plants a temporary umbrella
Wed, 01/25/2006
Surely that glowing orb in the sky for the MLK Jr. holiday was ‘old sol.’ Though it’s been nearly a month since we’ve been blessed with genuine daylight, enjoying it was like riding a bike again. We just walked right by the raincoat and umbrella, heading straight out the door for some communing with nature.
Though the dark clouds had a silver lining for a day or two, gardeners should be concerned that too much rain is too much of a good thing. Looking past the larger mishaps of falling trees from water-soaked soil, crumbling roadways along steep slopes and overflowing lakes and streams, gardens too may be suffering.
Waterlogged soils could result in mass drownings. Moisture sensitive plants, especially Mediterranean herbs and xeriscape specimens may suffer most. Like many Daphne species, they don’t like wet feet and are easy victims of root rot. Many newly planted spring bulbs may also be drowning in slow draining soils.
Containerized plantings may be suffering the most. Soils in containers tend to pack over time, plus the effect of composting organics, leaving a soggy, septic mess. That means trouble for any plant that doesn’t prefer boggy conditions. Wise recyclers will see another good reason for using several inches of packing peanuts on the bottom for drainage.
Bring over-watered containers under some cover — eaves, deck, whatever to relieve the deluge. After the constant rains have passed, be sure to bring them back into the open so they don’t dry out totally.
Q My soil is very heavy and I’ve had huge puddles of standing water for weeks. I’m worried about my lawn and other plantings. What can I do?
A The Lazy Garden is mostly a big pile of sand through which water moves quickly, allowing it to be easily dug same day as a heavy rain. It’s not so in many other gardens in Puget Sound. In fact, many locales present a few inches of loam over heavy compacted glacial till. Though true clay soils are rare in the area, compacted soils present a barrier to rain moving through the soil — especially where insufficient vegetation exists to act as a sponge. Those with hardpan soils may be looking out on persistent yard puddles, lakes even.
If your soil overlays water-blocking hardpan, make a note of the slowest draining areas. Some might be turned into garden positives using plants that actually prefer soggy soils. In sun, the butterfly-like blooms of gorgeous creatures like Japanese iris (Iris ensata) will seem to float across the garden. Combine with and variegated sweet flag (Acorus calamus) and cultivars of American native red and blue perennial Lobelia (L. cardinalis and L. syphilitica). Shadier marshy zones would prove great homes for Hostas and Rogersias,
Another choice involving a bit of engineer is to find a way to move the water. Of course, this would involve a lot of digging so those holiday pounds could be disposed of in a more meaningful way that running in place at a gym.
Drainage can be created by digging trenches about six inches deep into the hardpan. Dig to the hardpan and then dig deeper. Fill the trench with coarse gravel and lay landscape fabric (the non-degrading type) over the project to prevent soil from clogging those new drains.
Remember that water runs downhill. So to work, the system has to be planned in a way that moves water in the direction it’s going to go anyway. Moving it all to the lowest point in the garden is a great way to create that pond or bog garden you always wanted.
Alternatives to long distance transport include digging sumps every so often. Just large holes filled with coarse gravel and covered over with landscape cloth, sumps serve as underground retention ponds.
Theory is the water will slowly seep away into the subsoil over time. Mostly it’s another opportunity to work off winter pounds without paying the gym. These holes have to be deep — at least 2 to 3 feet to be effective.
The cycle from wet winter to dry summer means good gardeners need to plan for both — how to get water out of the garden in winter; and how to keep it on the garden in summer. So, you can see good gardening is more than plopping in a few petunias and walking away.
Gardening is an avocation that uses many skills of spatial design, color artistry, terra engineering, patience and optimism. A good gardener is a pretty well-rounded person!
E-mail inquiries and suggestions to lazy.gardener@comcast.net