Archive | September 2016

Fire in the Fields

Sumac lighting up a hill in Wisconsin's autumn

Sumac lighting up a hill in Wisconsin’s autumn

It happens every autumn. Huge sweeps of straggly, undistinguished shrubs that grew unnoticed in unkempt fields are suddenly, gloriously, ornamental. The long almost palmlike fronds of leaves shine bright red with hints of yellow and orange. The branches spread like candelabra holding up huge crimson fruit clusters that keep glowing long after leafdrop, when all the world is gray. No wonder gardeners think about bringing sumac in from the wild.

Staghorn sumac in the summer before changing color

Staghorn sumac in the summer before changing color

Sumac grows everywhere, all the way from zone 2 to zone 9. It grows in dry soil, poor soil, moist soil, near-bog, bright sun, and part shade. It spreads by seed and by underground runners that can travel 20 feet or more in search of a good spot to make a new clump of sumac. But if there is also a lawn anywhere nearby, there will be adequate local control as long as you keep mowing.

Smooth sumac (Rhus glabra) is the most common roadside attraction. It’s fuller and more readily clump-forming than staghorn sumac (R. typhina), named for the velvety down that covers every branch. Smooth sumac tops out at about 8 to 10 feet, staghorn at 12 to 16 feet.

Fragrant sumac makes a beautiful garden addition

Fragrant sumac makes a beautiful garden addition

Fragrant sumac (R. aromatica) is shorter, at 3 to 4 feet, and bushier, more like a garden plant. If you decide to bring sumac into your garden or prairie, no matter which type you choose you will need both male and female plants if you want fruits. Sumacs are available through nurseries that specialize in native plants, and some large garden centers will order them for you if you ask.

Note: it’s always a good idea to check whether a plant is considered an invasive species in your state before transplanting from an area where the plant is growing wild. In Wisconsin, the Department of Natural Resources provides a free guide to invasive species here:  DNR INVASIVE SPECIES GUIDE

 

When to Plant Trees

tree-planting-guide-diagramFor most trees, fall is the best time to plant. The soil is warm but not waterlogged the way it can be in spring, and trees without leaves make fewer demands on their roots to provide nutrients.

A few trees, however, including magnolia, birch, hawthorn, black gum, tulip tree, and most oaks, get downright cranky when planted in the fall. No one knows for sure, but researchers think that there is something that prevents the root structure from taking up enough water to overcome transplant shock, and that winter comes before the tree is ready for it.

Studies by Dr. Nina Bassuk at the Cornell University Urban Horticulture Institute in Ithaca, New York, show that transplanting these trees when they are smaller increases the success rate for fall planting. She has had much better results with trees that measure less than 2 inches in diameter at a point 6 inches above where the trunk emerges from the roots than she has had with larger trees. Be sure to water that new tree in well. Whether it has leaves or not, it needs water.

Watering also settles the soil and helps eliminate any air pockets. Dormant trees planted in October or early November should need only that one deep, soothing watering to last them the winter. But all that said, it is still better to plant magnolias in spring.

Like other things in life that aren’t what they used to be, burlap has changed. Whether for the better depends on your point of view. A single layer of plain old untreated burlap, now almost a thing of the past, rots away nicely and lets roots wander freely out of their soil ball. But you are just as likely to run into a plastic burlap-like material, or into burlap that has been treated with a rot-resistant chemical.

Both are popular in the horticultural industry for the same reason: they stay intact longer, through sunshine and waterings, as the tree makes its way from its growing site to you. But that perseverance presents problems for growing roots trying to find their way into new surroundings. Rot-resistant burlap takes years longer to decay than untreated does, and even untreated burlap presents a formidable boundary if wadded down in layers and left in place.

In both cases, these barriers restrict the diameter of the roots as they grow out. In some cases, the tree may even die. At that point, you can dig it up and use the original wrapping to take the dead tree to the dump.

To avoid such problems, after placing the tree in that nice extra-wide-but-no-deeper-than-the-ball hole, untie the twine around the trunk and cut away the burlap.

Note: some ideas are harder to kill than crabgrass. One of them is that when a tree is dug up to be sold, the branches should be removed to compensate for the loss of roots. The rationale is to balance root loss with the removal of an equal amount of top growth. The tree is then thought to be better balanced and better able to withstand transplant shock.

As logical as this sounds at first, it just doesn’t hold up. The human equivalent might be removing the right arm of someone who has just lost her left leg in an accident.

Transplanted trees need all the food they can produce to support the regrowth of those lost roots. The food comes from leaves doing their thing, so the more leaves, the better. The only branches that should be pruned are those that are dead, diseased, damaged, or rubbing against other branches.

Pruners

Pruners come in two basic styles: anvil and bypass. With anvil pruners you have only one sharp cutting blade, which closes against a dull bed (the anvil) to sever whatever. Bypass types are more like scissors, with two sharp blades, one of which secures the branch while the other moves past it, cutting as it goes.

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Anvil Pruners

Anvil pruners cannot be brought as close to the cut as bypass types, but they do have two advantages: only one sharp blade means only one blade to sharpen, and the mechanism does give a bit more leverage. Though this can make a difference if you want to use a small pruner for very thick or very hard wood, it’s usually easier to use a bigger pruner for heavier jobs and stick with bypass for everyday use.

Bypass pruners come with all kids of blade lengths and angles, with and without ergonomic handles, and in special versions for lefties. They also come in a wide price range, with the best-made costing two or three times as much as the cheapos. Fortunately, even the most expensive pruners cost less than dinner and a movie for two, so there is no reason to stint. Just remember the old saying: good tools make all tasks go lightly.

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Bypass pruners

In fact, it’s best to have at least two pruners, one saved for rough work (at ground level, for example, where you might hit gravel) and one used for delicate operations like removing spent lilac blossoms.

This will let you go a bit longer between sharpening sessions. But those sessions are as important as the pruners themselves because it is absolutely essential to make clean cuts when you are pruning shrubs. Wood that has been torn or crushed, as is guaranteed to happen if the pruners are not sharp, is (literally) an open invitation to disease.

Just as it’s better to plant a five-dollar tree in a ten-dollar hole than the other way around, it’s better to have a pair of sharp cheap pruners than to work with quality tools that have been allowed to get dull. If you don’t want to sharpen them yourself, be sure to have them sharpened regularly by a professional — your local nursery or garden center can usually recommend someone. Keep your tools clean and oiled between uses so they don’t rust, and they should serve you well for years.

Keep your Dahlias

dahlia-173799_960_720Dahlias will not winter over in places where the ground freezes, but they are easy to store if you have a cool place to keep them. Start by making labels while the plants are still blooming, so you remember which color is which. Wait until frost kills the top growth, then as soon as there is a dry day, cut off the dead foliage leaving stubs 2 inches long. Use a digging fork to lift the tubers; turn the clumps upside down.

Let the tubers dry a few hours, then gently remove as much soil as possible. Don’t wash them off, as the last thin layer of clinging soil will help protect them from shriveling. Line a large box with a plastic bag; then add a 4-inch layer of coconut fiber, dry shredded leaves, styrofoam packing peanuts, or sawdust. Place tubers stem side up on this bed, keeping them well separated. Nestle the labels into the clumps.

Completely surround the tubers with additional packing material, and loosely close the bag. Store in a dark place, ideally at 35º to 45ºF. When storage temperatures climb to the mid 50s, the tubers will start sprouting. Ignore short sprouts; they’ll be buried when you plant. Clumps that come from storage with long, pale stems, however, should be hardened off before being set out into the garden.

Dahlia tubers

Dahlia tubers

In the spring, as long as there are a couple of healthy-looking eyes (the buds from which the plants grow, located up near the old stem), even rather shriveled tubers will make decent-size plants. If shoots have started to grow, evaluate them before planting. If they are still small (less that 2 inches long), just bury the tubers as you would normally, a couple of inches below the soil.

If the shoots are long and pale, they will be too far along to bury completely; they’ll also be brittle and vulnerable to sunscald, so handle carefully. Toughen up the shoots by putting the tubers with their new growth in the shade for a week or so before planting. Plant the tubers at the normal depth, with the long shoots above ground, and continue to protect the shoots with a light sprinkling of straw for the next week or 10 days. The idea is simply to shade the bleached growth until it turns green, so don’t smother it with a heavy layer of mulch.

Plant Spinach Now

There’s a certain sadness about autumn cleanup and shutting down the garden. But one of the things to lighten a gardener’s heart is to seed some cold-tolerant varieties of spinach in the fall and let the young plants overwinter. By giving them a head start, you ensure that you will be eating fresh spinach salad next spring while your friends are still waiting for their seeds to germinate.

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Delicious spinach waiting for harvest

‘Fall Green’, ‘Vienna’, and ‘Winter Bloomsdale’ are varieties recommended for overwintering. Planting them up to the second week of October gives them a chance to develop a few leaves and roots before winter. They don’t need to be mulched; the leaves will get ratty through the winter, but the root system will be fine. When spring arrives, new leaves will sprout from the established root system.

If you have saved seeds, make sure they’re a variety that is designed for overwintering. If not, you can hold onto them until next spring. Theoretically, spinach seeds remain viable for three years if stored cool and dry, but germination rates often start falling by the second year.