Winter Garden Activities

Some winter garden activities:

Trim monkey grasses.
Trim ornamental grasses.
Prune shrub and hybrid tea roses.
Prune climbing roses.
Weeding.
Prune Hydrangeas, if they flower on new wood.
Begin planting your winter vegetable garden: onions, greens, beets
Begin indoor seeds for summer vegetables.
Watch your daffodils and crocuses and make a note about where to plant more in the fall.

Creepy Crawlies

 

If you have boxwoods, you probably know that now is the perfect time to prune them, during their dormancy. While I was out pruning yesterday I also ran into these fauna: boxwood leaf miners (Monarthropalpus flavus).

I have been learning about them over the last few years but am reading up again as I do most winters. There is always something to learn.   One source says that the Boxwood leaf miner is most common on American boxwoods, not seen as much on English or Korean boxwoods.

So what do we know about them? The boxwood leaf miners emerge as adults in late April to early May depending on the temperatures. The adult is a flying insect which briefly lives to deposit eggs in the newest flush of spring leaves. Then the larva grows in the leaf until next spring.

These creatures were on a series of dwarf boxwoods in a south Nashville garden. There are large boxwoods on the property, probably English, that showed no signs of leaf miners.

 

Here, note the front and back side of the leaves;  both sides look blistered. The affected leaves are only at the outer several inches of the twigs. Inside the blisters are larvae which are growing between the leaf’s front and back surface. If you carefully tear open the leaf, you may find a larva. Or two.  Maybe wiggling. Tiny yellow bits of life.These larvae will pupate this spring. And start the cycle again.

How bad is this? Depending on who you ask, not so bad, just an aesthetic buzz-kill.  Or they can weaken and kill your plant over time. I cannot give specific treatment advice,  but there’s plenty of research to be found on chemical controls. I have also heard about a wasp predator, either the Diglyphus isaea or possibly Dacnusa,  which might be worth learning more about.

Happy pruning!

Winter Thoughts

Now we have gorgeous 50 degree sunny days – this is my kind of winter weather. I even went out to my veggie garden and pulled out some chickweed/dead nettle out of the strawberry patch. Barely made a dent but it was satisfying anyway.

I have been hearing frequently this fall and winter about these two disease issues, so here’s what I understand about 2 prevalent problems in landscape flowers that might affect us gardeners this year.

Impatiens disease
A downy mildew is infecting Impatiens walleriana (common shade Impatiens) and possibly some wild Impatiens in 32 states or more as of the fall of 2012, mostly east of the Mississippi River. There is debate about whether there are effective chemical controls right now.

Certainly for homeowners, an IPM (Integrated Pest Management) approach will be most useful. [Integrated Pest Management is an attitude towards plant health whereby we look at the whole picture before reaching for a sprayer. Consider these components in any a problem situation: Horticultural requirements like shade/sun tolerance and pH and nutrition needs; abiotic causes meaning what might have caused the problem that wasn’t a disease or insect; weather, storms, etc that might be contributing; human and pet impact; identify symptoms before making conclusions – sometimes an insect pest or a browning of a plant came after some other injury or malady.] [Just one example: There’s a lovely shade bed full of Hosta and in April the gardener notices dozens of holes in the foliage. Gardener does a careful inspection and can find no insects in sight. But there was a hail storm the week before. One very likely explanation!]

IPM for Impatiens downy mildew calls for rotating crops in planting beds, possibly preventative fungicides, and removal of affected plants. Some nurseries are effectively using fungicides on their market plants. This will not provide protection from spores remaining in soil from past infected plantings. Note that you cannot identify the infected plants by sight, so buying a healthy looking plant at the garden center doesn’t mean the mildew won’t appear later.

For most homeowners, unless you want to spray a fungicide weekly, it’s easier to try planting a new variety of bedding plants this year. For shade beds, try New Guinea Impatiens, which are suggested as disease resistant, or try annual Begonias, or Hypoestes. Vinca (annual) may do well in mixed sun/shade beds…hey, you could even migrate to perennials: some smaller Hosta and Hardy Begonias will provide a full ground cover, though with not quite the color coverage of Impatiens.


Rose Rosette Disease
Rose Rosette disease has been showing up in roses for several years but is now being talked about frequently in the nursery and landscape industries.
• All types of roses are susceptible but shrub roses (including Knockout roses) are particularly prone. • Rose rosette is a viral disease, spread by mites, which are most active spring to September.
• Symptoms are: deformed leaves and flower buds, excessive reddish foliage, thick clusters of small stems (“witches broom” effect) , and unusually thorny stems.
• RRV is systemic to the plant, but does not live in the soil.
• If the plant becomes systemically affected, it may die within a few years.
• Vines, ramblers, and well-pruned hybrid teas are less likely to be hosts.
• There is no cure at this time. Prevention efforts with an IPM (Integrated Pest Management) approach may reduce chances of getting the viral disease. IPM goal is to create an environment less prone to infection, and to target the vector, a wooly mite.
• The mite that transmits the disease can travel on the wind, for many miles. The mite is tiny and invisible to the human eye without magnification.
• Heavily pruned roses are less susceptible to the disease. A spray of horticultural oil in winter just before dormancy break may help slow the problem by knocking back some of the mite population. • It is unclear if a repeat pesticide treatment during the growing season is effective. If you treat your roses in spring for Sawfly with a neem oil, it won’t hurt any other IPM efforts for RRV.
• Plant climbing roses or ramblers which seem to be less susceptible than shrub roses.
• Plant and prune so that plants do not touch each other, to avoid cross-contact
• Remove and destroy any infected rose. Don’t put this in the compost.
• http://www.ars.org/pdfs/rose_rosette.pdf
• http://www.ca.uky.edu/agcollege/plantpathology/ext_files/PPFShtml/PPFS-OR-W-16.pdf

The good news is there are a lot of other beautiful plants we are growing that will give us flowers throughout the year. Plenty of hardy plants around that don’t play victim very often to pest problems: daisies, sunflowers, zinnias, the almost fool-proof butterfly bush, hostas, beautyberry, hardy azaleas, the ever-tough coreopsis, annual vinca, and so on.

Winter Garden To Do List: Prune and thin boxwoods in February. There is more than one school of thought about boxwoods, so do some research. I go with thinning in the dormant season, to open up the interior for air flow, sunlight, and deadwood removal. This can be done with or without the ‘clouding’ effect. Prune roses on a dry cool day in February .

  Trim ornamental grasses including monkey grass. Do not trim sedges. For smaller grasses like Little Bluestem, Miscanthus, etc, I use hand pruners or ‘secateurs’ as they are known across the pond. For large grasses that are hard to handle like Switch grass I usually have a helper and gas powered hedge trimmers. Tie up the base of the plant, maybe 12-15 inches above the ground, with some compostable twine. Then have the very trusting helper hold the top so it doesn’t flop around. Carefully watching all things non-plant, announce that you are starting to cut, and then run the hedge trimmers smoothly through the grass stems. Rake up and compost the trimmings. With all things involving cutting, use sharp tools, and clean the blades with alcohol between species or between any individuals suspected of disease.

Plant winter vegetables including greens, onions, beets. I wait until February to start my beets and onions. But greens –collards, kale, spinach – are pretty cheap as seed and you can start planting a series of rows, every couple of weeks until really warm weather.

Winter Woody Ornamentals

I'm not talking about Christmas trees or Yule logs either!This one's about shrubs.

I am a big fan of flowers…bright disks and rays and beards and panicles in spring and summer show. I can’t get much more excited than when my first Echinacea blooms or the Ironweed emerges in purple drifts. And a big show-off Bearded Iris can’t be ignored. But fall is when I really notice shrubs. I’m not talking about evergreens right now; hollies, boxwoods, yews and laurels  are great helpers in the yard and garden. They give us year round color, and stability in the visual scheme. But right now is when I notice the subtle textures, colors and promises of deciduous shrubs.

A Calycanthus (Carolina Sweetshrub) at a Nashville garden is a bare twiggy thing right now (late November) but has crunchy pods of seeds at its tips. The seed just reminds me of next year’s delicate magenta flower.  If you prune a little right now, you’ll get the sweet tangy aroma from the cuts in their wood.

The Witch hazel leaves are yellowing, but I know their flowers are imminent. This is part of the fun of a garden in winter; like Helleborus, Witch Hazels flower in December and January. Their cousin, Fothergilla major, saves its blooms for spring, but is turning a gorgeous yellow and orange on its last leafy legs. I like the shape of this shrub too: a smallish upright branching plant, which like the Calycanthus has a lovely spring flower. It’s a 3 season plant.

Cotoneaster is bronzy colored and full of berries, Rhododendrons are glossy and green with next year’s buds curled up tight.

This Viburnum snowball bush is getting ready for winter now.  Sure, it will be a show off in April with its huge round hydrangea-like ball of flowers. But look at this color right now:  rich  brick red and yellow.

Oak Leaf Hydrangeas (Hydrangea quercifolia) situated in sun are a deep purple red.

And of course there are Crape Myrtles (Ligustrum) which really are more tree-like, but I have a few that I keep pruned smaller for my convenience. The leaves are gone, but the smooth sand-colored trunks catch and reflect the winter sun and give a sculptural effect.

The appeal of shrubs in fall is more are more subtle than the maples, poplars, and oaks showering leaves down on our yards now but I like their gentle bits of color and shape. I appreciate the details that we overlook at other louder times of the garden year.

(See the easiest to understand description of why leaves change color, here:   http://biologicalthinking.blogspot.com/2012/11/natures-crayons.html#links)
 

(Pictured, in order: Fothergilla major 'Mt Airy', Snowball Viburnum, Hydrangea quericifolia 'Pee Gee')

There are Flowers in Your Future

This is it! The perfect time for planting, when the sun is shining, the air is cool, the ground is still workable, and winter rains are on their way. Winter is when most deciduous shrubs and flowering perennials go dormant. That is, the plants are not creating new stem and leaf growth, they are at rest, most of their activity is in their root systems. A perfect time to put a new shrub or herbaceous perennial in the ground. Transplant shock is milder when the plant is ‘sleeping’. The owner   -that’s you-   doesn’t have to water as vigorously or worry about the brutal heat of summer.

Yes, you should water as soon as you plant, and water your plant several times in the first two weeks. Right now, November 2 in Nashville it’s very dry and no forecast for rain, so water for the next couple of weeks.

What about the cold you say? “It’s too cold for that sweet little tree.” Nope, the ground is an insulating ‘blanket’ for all the plants. Just keep it watered if we have dry weeks.  Now, your plants in pots…different story…you should bring them into the house or garage, especially if they are tropicals (e.g., ‘houseplants).

After you’ve planted your tree/shrub/flower…a little mulch won’t hurt, but a little goes a long way. Use no more than 3 inches of mulch on your flower beds and around trees. Repeat after me:  “Mulch Volcanoes Kill”  - see this link, sweet and simple:

http://www.maine.gov/agriculture/pesticides/library/ppt/Master_Gardener/mulch_volcano.pdf

A LOT of mulch is not a good thing. It’s bad. Don’t do it. Just because ‘they’ do it…doesn’t mean it’s good horticultural practice.

Back to planting:

Plant your spring-blooming bulbs now and into December: crocus, hyacinth, daffodils, tulips, frittallaria. Yes, the ones at the Homeowners Depot are just fine, and affordable. Follow the depth planting instructions. For most bulbs, dig a hole this deep: the diameter of the bulb times 3. Example: the crocus bulbs are about  ½ to 1 inch wide, plant them 2-3 inches below the surface. You don’t need to water these, they will be fine on their own.

You can still plant pansies, too, and ornamental cabbages if that’s your thing. Put on a light sweater and enjoy some of Tennessee’ best weather ever out in your own God’s Little Acre.

Blooms & Buzz

Here are some late summer flowers and their insect friends. In the last few weeks I have been stung about once a week by some sort of critter. A wasp reacted when I was cleaning some daylilies where it must have been hovering in the morning shade. I ran my lawn mower over a yellow jacket nest  and you can believe they did not like that, but I was lucky to escape with only one sting. The visual must have been amusing: Dance of the Yellow Jacket Attack. And finally I was opening a gate and brushed aside a gorgeous plume of goldenrod and got nailed hard by a bumblebee. Can I get a break? For sure I'm watching more carefully now where I put my hands, and tools. The yellow jackets are particularly disturbing to me, they build nests in the ground in a hole, you feel them before you see them, they hover around very busily all day and they will be with us until the first hard frost. That section of the grass will remain unmowed for now.
We need all these critters though.
Yellow jacket larva feed on many crop-damaging insects. Bumblebees and wasps are pollinators, and many wasps and yellow jackets eat aphids, which is always a good thing in my  book.

Here are some bumblebees on  Sedum 'Autumn Joy' in my yard, and a monarch (?)  butterfly caterpillar on some parsley (Petroselinum) at the Demonstration Garden at Ellington Agricultural Center (both in Nashville!). Oh and just a snap of some Spireas in full late summer bloom at a private garden.

PS Though I have never had an adverse reaction to an insect sting I always carry a first aid kit at work, with some benadryl in the meds section.

Its Summer! What to do, what to do.

It seems like it’s been summer since about April 1. June was unusually warm, July was downright brutal, and now we have August which is normally our hottest and driest month of the year in Nashville.

Had enough yet? I went to the Adirondack Mountains in New York for a week, and highly recommend becoming very wealthy so you can spend a whole summer up there. However I love Tennessee and our beautiful  Springs and Winters. I love coming home to see my sunflowers in bloom and the beautyberry bush starting to put out fruit.

It was still hot when I came home, so my garden “TO-DO” list is pretty short and is headed up by:

1. Stay inside in the air conditioning after 1 PM. (Remember that I work outdoors, in gardens, so, by 1 pm I have been outdoors for 6 or  more hours.)

2. Don’t prune heavily on most plants during heat/drought stress.

Light trimming of these will be alright: yews, privet, hollies, and Knockout roses. But don’t prune hard on most shrubs; removing a lot of foliage will cause further dehydration.

3. Fertilize thoughtfully.

Shrub roses: don’t fertilize your shrub or knockout or hybrid roses after about August 15. A flush of nitrogen-induced growth can create tender new leaves that can be stressed by early hard frosts. Our typical first frost date is Oct. 15, so 6-8 weeks is a safe window. Same thing for nitrogen fertilizer of many evergreen shrubs (privet, boxwood, yew, holly); don’t fertilize after August 15^th. Wait until winter when the shrubs have gone into dormancy.

Fertilizing shrubs:  It is alright to fertilize lightly with a slow release and/or organic fertilizer after dormancy begins. During dormancy (winter) the plant is primarily active in its root system, not the foliage, so phosphates are appropriate. From late October through January,  applications of an organic or slow release fertilizer on shrubs is fine, especially a phosphate fertilizer.

  4. Watering

Moist, even, watering of shrubs, perennial flowers, and lawns. An average rainfall for continued plant health is one inch per week.* The soil stores a lot of water for a long time. Middle Tennessee was in an unusual drought for most of the summer. We are almost up to normal rainfall levels now, after the July rains.  Let the soil dry out just a little between watering, a couple of days. Most plants don’t like ‘wet feet’, as it leads to fungal diseases in the roots.

* How do you know if you’ve watered enough? With a sprinkler, set out a tuna can, run your sprinkler, start a timer or watch your clock. When the can is full that’s the amount of time you need to run your sprinkler . Every 3 or 4 days. In the morning. Not at night. Not in the hot afternoon.

With a soaker hose system, place the tuna can under a section of hose, measure again as above. You can remove the tuna can once you know your time measurement.

5. Don’t worry about leaf drop with your trees.

It’s typical in August to see a bunch of leaves, especially hackberry leaves, on your lawn and driveway. Don’t  run out and look for something to spray or inoculate. Don’t  do extra watering. In August there is quite a bit of NORMAL leaf drop. Especially  hack berries, and tulip poplars, redbuds, and river birch. This is normal leaf drop in August for ‘sustained growth’ trees. The  tree is not abnormally stressed.

Also, some trees will drop twigs and these are some likely causes:  2011 cicada damage, and squirrel twig chewing or twig girdler damage. None of these conditions require treatment. Maybe just some lawn mowing. (Again thanks to David Cook for the recent  informative diagnostic lecture.)

6. Plan your fall. Again in the air conditioning, with the Olympics on TV in the background, plan for fall activities such as applying a  pre-emergent herbicide, garden cleanup, and doing  fall fertilizing.

7. Continue deadheading (or ‘debudding’) your repeat bloomers : Echinacea, brown eyed susan,  roses, zinnias, dahlias, catmint, even Salvia

8. Control mildew diseases with liquid copper  or a stronger  fungicide. Garden phlox is still prone to powdery mildew with the high humidity.

9. Control unwanted vines and weedy  brush with hard pruning and glyhosphate applied to the cut end.

10. Do a soil test.  First because you really can benefit from learning about the pH levels of your soil. It's easy and cost $7 plus your time to take it to the soil/plant/pest lab at Ellington Ag Center. http://soilplantandpest.utk.edu/soil/index.htm