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Excessive Rainfall & What to do.

[September 2009 - and still valid today] With the unusual variances in heat/cold and dry/wet over winter, many gardeners are scratching their heads wondering what is coming next. The most common question this summer has been about how to deal with the seemingly unending rainfall in many areas of the USA. Here in the Pacific NW, where we are located, there has been three back-to-back soggy springs of below normal temperatures. Then, after Dianna planted cool crop veggies based on the previous two years of trying to grow long season veggies, we went into 8 weeks of near normal days but no rain. The cool crops bolted, but the last minute small planting of heat lovers rejoiced.

Plan now for success, follow our suggestions and prepare your garden now before winter.

Customers located in Massachusetts reported over three solid weeks of rain in June and even perennials rotting on top of the ground. One said, tongue in cheek, that he was thinking of opeing up his acreage to a duck hunting club. Customers in the Northeast reported problems with fungus on lilies, black spot on roses and peonies. Upstate New York thought winter was never going to end, waiting until nearly August for "spring" and even the Midwest had their share of record cold and wet.

Lilies have three major requirements for success, drainage, drainage and drainage. They like their planting ares to be evenly moist, and not wet for days on end. Anytime you see premature yellowing to the leaves and especially if you are seeing stunted stems as well, it always means there is too much water around the lily bulb. The only time you should see yellow leaves is on a healthy plant in the fall when the bulb is maturing.

So now, what to do? As we are harvesting your newly purchased bulbs this month, plan now for success next year in your garden. Assume that areas in your garden that you have always felt were well drained, could next year be possibly more suited to water lilies than to true lilies. Some customers in the North East who never had problems in years past, experienced drainage problems this past spring. In “normal” years, their ground was indeed well drained, this year, it wasn’t. The old adage of “an ounce of prevention being worth a pound of cure” comes to mind.

We have always recommended raised beds to customers who were concerned about drainage. In wet areas or with heavy clay soil, a raised bed at least 8 inches above grade can make all the difference for many types of bulbs, roses, and other perennials. Lily roots are allowed to penetrate into the original soil, but the basal plate (where the roots attach) is safe from excessive moisture and danger of rot.

A word of caution: Newly prepared beds do not have soil compacted sufficiently until after one year of irrigation. During winter, plants in non-compacted soil can suffer damage in severe winter areas from freezing. In areas were winter temps. go below zero; be sure to mulch AFTER your ground first freezes. To mulch before your ground freezes invites voles, shrews, and mice to move in to stay warm and upon finding soft soil, can and will dig down to your bulbs. Remember to remove the mulch in early spring so that if rains are heavy, your soil does not become waterlogged causing bulb rot. It is generally not the cold that causes problems with “hardiness”, but rather excessive moisture or repeated freeze-thaw cycles. Lilies, once their ground is frozen, like to stay frozen until spring. In the spring consider leveling off any settled areas to insure your lilies are still at their proper planting depth.

Should you find a raised bed to be the best solution for you, and you plan to buy a load of “soil”, know what is in that “special blend” your local landscaper is offering. Lilies do not like wood products and many of the custom blends of soil are extremely high in ground up wood waste to which a little sand is added and just enough peat to make it look like “real” dirt. If you can smell rotting wood, your lilies are not going to be happy. Should you decide to go to one of the big box stores and purchase bags of “soil” smell it first and also check for additives. If it smells like rotting wood, don’t buy it for your lilies. Most pre-fertilized bagged soils are far too high in nitrogen for lilies as well. Nitrogen levels over 10% can cause bulb rot, especially in Orientals. Never purchase a soil that has been pre-fertilized, as lilies do not need it when planted and if new root growth hits a grain of fertilizer, it will burn and quit growing. Everything needed for growth next year is already stored away in your bulb from this season’s growth. It is usually best to work with your native soil and make any necessary adjustments. Clay soils need to be lightened up, sandy soils need some organic matter added.

Clay soils are commonly described as adobe, gumbo, or just plain “heavy”. It is composed of small mineral particles which are generally flat in shape and form a close bond with one another. Water and air have difficulty passing through these tightly bonded particles. In clay soil, oxygen is not supplied as readily to the roots and your bulbs will suffocate if given too much moister. Add sand or our preferred additive is perlite, along with a small measure of compost or well rotted manure to lighten the soil mixture.

Sandy soil never “puddles” with particles generally more rounded in shape, and does not stick together when moistened. Sandy soil allows air and water to pass freely, but usually needs to be amended with additional organic materials such as compost or well-aged manure.

Loam (the gardener’s dream) is a natural mixture of clay, sand, and organic materials which are fast-draining and naturally fluffy, allowing soil to stay moist but not soggy between watering cycles. Use caution in adding too much organic material to this type of soil, as too much moisture may be trapped around the bulbs, causing rot. Reports from our customers in excessively rainy areas this year have told us this is the type of soil they have. Never has it been a problem in the past, but this year it was. If you have a good loam soil, you, most of all, should consider working in drainage material when planting just to be safe in the years to come. Remember, “An ounce of prevention. . .”

We have always recommended adding about 20% perlite to your planting mix for increased drainage if you do not have a naturally quick draining sandy soil. Perlite is the white crunchy stuff. Do Not add vermiculite as it holds water. We have had customers confuse the two when they go to their local nursery and only remember it was something with “lite” in the name.

We recently heard from a woman who had drainage problems last year and when constructing a new raised bed, last summer purchased bags of landscape lava rock from her local building supply store. She liked it because it looked more natural than gravel and was easy to work with. Her report this year was the new bed with the lava rock produced “the best lilies I have ever seen” while her main flower bed suffered from excessive rains. “Hubby” has built a new bed, and this fall all of her other lilies are being moved. She was so taken with the results of the lava rock that she is now adding it to her garden beds every time she divides or plants something new. As she said, “I can always add more water if needed”. Take a few extra minutes when planting and work some of this material in under each bulb or beneath the roots of other water sensitive plants such as roses. Lava Rock is something we had never considered and feel this is probably the best tip we have received in the past few years. Even after over three decades of lilies, we still learn from our customers.

A word of caution. Should you find the new recycled tire mulch and think it might be the way to go. . . don’t. Should the rubber compounds leach out into your soil they could bring about a whole new set of problems.

FALL CLEANUP: As your lily stems begin to yellow, don’t let the leaves fall to the ground but rather cut your stems off at ground level and dispose of them. Do not compost as if there are any botrytis spores, when you add your compost back to your garden, you are potentially causing the spread of fungus. This was an unusually bad year for all types of garden fungus across the US. Roses and peonies covered with black spot and lilies fighting off botrytis. Both fungi like lots of moisture and temperatures in the mid 60’s to upper 70’s as being “prime” for spreading. When spraying your roses, spray your peonies and lilies at the same time. Any quality systemic rose spray is fine for lilies. Should botrytis take a foot hold, copper based sprays are very effective. The down side is they leave a blue/green residue, but copper does halt the problem. Just about everyone with concerns with overly wet gardens this year who contacted us followed up with “my lilies are getting brown spots on their leaves and flowers”. . . just like the stuff on my roses. One customer reported that she was spraying with baking soda because it was more organic and found that it was effective in keeping the black spot on her roses in remission. Her mix was one tablespoon of baking soda per gallon of water and it needs to be reapplied after a rainfall. The baking soda creates an alkaline environment on your plants leaves that fungi spores do not like and do not grow well in.

Ways to avoid botrytis from getting a start? One of the most simple is providing good air circulation. Dry leaves make for a hostile environment for fungus. Leaves that are always wet though much of the morning from night dew or rainfall can give botrytis an early foot hold. Air circulation is the key to growing most garden ornamentals successfully. Avoid watering in the evening causing your leaves to remain wet all night. When watering, try to water the base of the plant rather then from overhead. If overhead watering is your only option, air circulation becomes all the more important. As flowers begin to fade, consider snipping off the spent bloom as you would a rose rather than allowing the petals to fall to the ground. A good garden clean up in the fall removing fallen leaves from you lilies, roses, peonies, and the like will result in fewer areas for botrytis and black spot spores to winter over waiting for the moist, cool days of spring.

All in all, Lilies are extremely easy to cultivate given drainage concerns are addressed. If you ground drains well, your lilies will flourish. Having essentially the same requirements as roses, they are not nearly as fussy. An order that just came in had a notation “I am giving up on my Hybrid Tea’s; your lilies are so much easier”. Take a few extra minutes this fall while planting to insure unfettered success for years to come.
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