Should we fertilize shrubs in the Fall?

>> Thursday, September 25, 2008

The one thing that is constantly on my mind, where gardening is concerned, is feeding. Am I feeding my plants enough, am I over-feeding? Plants can’t tell me when they need to be fed. Oh sure, there are the usual signs that they are not getting enough, such as, drooping, discolored leaves and lackluster flowering. But by the time plants are displaying these dismal cries of starvation they are already stressing.

I want to have a plan that will provide all the nourishment my garden needs without over feeding or waiting for these obvious signs, which also stress me.

While I ponder this seemingly unanswerable problem of achieving the proper balance, I see ads from nurseries promoting fall fertilization. I never considered that anything should be fed this late in the season. Apparently, I have been remiss in my shrubbery duties. Being the skeptic that I am, I can’t help being a little leery of this latest bit of advice from someone who sells things for a living, because I am sure they want to get rid of any overstock they may have before winter sets in. Secretly though, I do believe they don’t want to give out bad advice, it just wouldn’t be in their interest to do so. Skepticism dies hard.

So, after searching for a solution to this constant source of a headache, I have learned that, yes, you should feed woody plants, such as shrubs and trees. But, and there is always a but, right, timing is very important.

Keeping in mind that fertilizing produces new growth, and that tender growth spurting forth just as frost is about to hit us and would therefore threaten the very life of the plant, feeding has to take place at just the right time. Of course, this timing will vary by region, but application of a fertilizer specifically made for shrubs and trees should be applied when three conditions are met: all new growth has ceased, daytime temperatures have begun to moderate and the soil holds adequate moisture. In other words, when plants seem to have given up producing anything new and just want to take a vacation from providing us with their beautiful foliage and flowers, day/night temperatures are staying fairly constant each day and are low enough that you have switched from wearing shorts to wearing long pants and a sweater when out in the garden, and there is no longer competition with the hot sun to evaporate every drop of water you are painstakingly pouring onto your garden. As a rule of thumb, about two to three weeks before your average first frost date, which, in my case, is about four or five weeks into football season.

One of the old time, and still very valid, rules of gardening is that you feed the soil and the plants will fend for themselves. The kingpin in making this rule work is, of course, compost. You can use your favorite designer chemical fertilizer, but compost is the very best way to go. There are many wonderful websites and blogs covering how to make compost, and truly, all of us throw stuff out everyday that could go into making a compost pile, large or small. Once you get one going you will be absolutely surprised at how easy it is to maintain a compost pile.

There is no such thing as bad compost. Except, of course, for toxic or nuclear waste, or if it is really, really so smelly that your neighbors complain about being in the same neighborhood with it. But aside from those easily avoidable situations, compost is king.

In nature, shrubs and trees are constantly nourished by the natural cycle of falling leaves and the soil micro organism activity that this natural compost supports. If you just keep this in mind and try to duplicate it on the very small scale that is your garden, you should do just fine. Shred the leaves from your trees, or talk your neighbors into giving theirs to you by convincing them that using them will help keep the smell down from your compost, and sprinkle them over your garden or, better yet, add them to your compost and sprinkle that over your garden.

So, for one final time of the year, feed your woody shrubs to nourish the root growth that is taking place to store reserves for next years growth. Your shrubs will have better foliar color, larger leaf size, and superior growth next year.

As always, be part of the solution and remember the future.


Insect/Disease Update

>> Friday, September 19, 2008

With the change in the weather, there seems to be a decrease in the insect activity in my neck of the woods, except for the bees that is. I have several shrubs that they are going crazy over. Buddleia Black Knight and Caryopteris Dark Knight and Caryopteris Sunshine Blue.

In the latest Small Fruits and Vegetables IPM Advisory from Utah State University, trap counts of most insect pests in field monitoring sites were at zero this week except for beet armyworm.
Beet armyworm mainly attack cool-season crops like lettuce, spinach, broccoli, etc. They also attack peppers. So if you see fine strands of silk begin looking for this little pest because it can defoliate your plants.
Here's the adult. USDA Agricultural Research Service has a good description of its characteristics and life cycle here.

Cucumber beetles continue to feed on cucumbers, melons and squashes. Since the day length shortens and nights are getting cooler, they will begin looking for places to overwinter, such as under plant debris (clean up the area), in cracks and crevices of wood, etc. Signs of their presence includes chewed leaves, stems and blossoms, and scars on fruit rind. Cucumber beetles can also spread squash mosaic virus. The virus is only spread by the feeding beetle, or by infected seed, not from plant to plant. Symptoms are distorted, blistered leaves with light green/dark green mosaic pattern. Fruit can be distorted and have a mottled pattern on the rind.

I recently began harvesting pumpkins, these are Orange Smoothie, to enjoy them as pie and other deserts. The only thing that really bothers them this time of year is powdery mildew. It won’t directly affect the fruit but a bad infestation can cause a stem to weaken. If you have more self control than I did and are not going to harvest for awhile, consider an application of powdery mildew control.

The best control I have found is a baking soda wash:

1t baking soda, 1 quart water, a few drops of mild liquid soap, not detergent, or light vegetable oil to help the baking soda stick. Optional: add 1t light horticultural oil.

It is also a pretty good treatment for black-spot on roses.

Also, if you feel up to it, you can remove a few leaves to improve air circulation. Overhead watering, especially late in the day, helps to spread this fungus so try to water early in the day and if at all possible water beneath the leaves. I know it isn’t always easy to do so, so just make up some baking soda wash next time you need it.

Hope you are all enjoying the cooler nights and getting the garden all cleaned up for next year. Even though we still have a lot of gardening left this year, time flits by before you know it.


Autumn already?

>> Friday, September 12, 2008

It seems like just yesterday….

I don’t know why summers seem to go by so quickly these days. They say that as you grow older time does seem to fly by faster. I am beginning to see the truth to that statement.

Since the night time temperatures here at nearly one mile above sea level in the Utah valley are dipping into the 40’s the call to dig out my Fall work list is getting stronger. It seems I cannot put it off any longer.

I finally relented and planted a Geranium, at my wife’s insistence, this year. Don’t get me wrong, I like their foliage and flowers but they seem to get leggy, although this one didn’t, and they need to be dug up every year (this is the true reason I resisted planting one). So, now the time has come to add this chore to my list. Oh, I complain but it isn’t really that big of a deal. The first step is to cut back the plant so it will be easier to dig up. Wait a few weeks for it to recover from the trimming before putting into a container. I am going to also take some cuttings for new geranium starts. Over the winter they will be grown in bright light with cool temperatures. We have a food storage space in the basement that would be just about right for this as the garage would tend to get too cold. There is an excellent post at Ventnor Permaculture that addresses how to take cuttings.

Now is a great time for bargain shopping at nurseries. Which is great because early fall is also an excellent time to set out new perennials to fill in those empty spots that are a constant reminder of past failed plants. Also, dividing and re-planting spring-blooming perennials should be done now so they can get rooted before the ground freezes. Use a spading fork to lift plants and divide them.

I have several Chrysanthemum Alaska that will be divided next year. They have grown in size since planting last year but have not yet begun to die out in the center, which is how you can tell they need to be divided.

The next three plants will all keep their heads this year to both feed the birds and hopefully drop some seed onto the ground in order to start new plants.
Bee Balm Monarda Blue Stocking

Echinacea Magnus

Echinacea Bravado

The Black Eyed Susan (Rudbeckia Goldstrum) has already started some new plants and I will leave them untouched, also for the birds. The Goldfinch especially loves picking seeds right off of the heads.

Earlier this year, I dug some daffodils up to divide them and to move them to a different location. September is perfect doing this so they can establish roots while the soil is still warm. They need to be planted deep, with at least 7-8” of soil above the nose of the bulbs. Deep planting assures they will last and multiply for many years to come. Hopefully, the spot I put them in will be their final location, but who knows, plans are always open for change.

September is also a great time for planting "hardy" pansies for both their late-season color and to get an early start next spring. This is one annual that will actually survive winter to return early in spring. They will grow and bloom well into December. This photo, Delta Violet Face, is from spring 2008 which was planted in winter 2007.

Herbaceous and tree peonies can be planted now in full sun where the soil has been enriched with compost and sphagnum peat moss. Don't plant too deeply because that can cause failure to bloom. I haven’t grown Peonies yet but the neighborhood I live in have had success with them.

Cooler temperatures mean a sort of mini re-birth of the perennial garden. Plants that were stifled during the heat of summer are beginning to respond and grow with cooler conditions. Aster’s are known for their fall bloom and are usually tall 24” up to 48”. This Aster, Snowdrift, was supposed to grow to a height of only 6” and 24” wide and makes a great groundcover.
The first photo shows one which gets all day full sun, and is now 8” tall and has spread to 40” across, has been developing small white buds for several days now and some are beginning to open. This plant will soon be covered with bright white star-like flowers.

The second photo shows another one, in a different location, that is overshadowed by dozen or so Zinnia California Giant opened its blooms about a week ago.

As a side note, if you are experiencing problems with powdery mildew, now is a good time to get a handle on this fungus. You can control the spread and kill off a bunch of spores to lessen the problem next year by spraying a baking soda wash on the plants. Prepare a the wash by mixing 1 tablespoon baking soda and 1 tablespoon vegetable oil (canola oil or dish washing soap works too, it helps the mixture stick to the plants) into 1 gallon of water. Pour the mixture into a tank sprayer and apply to upper and lower surfaces of leaves. Doing so will inhibit the germination of the fungus spores.

This is just the beginning of Fall clean up, and if you take it one step at a time so you don’t overwhelm yourself at the last minute, it shouldn’t be viewed so much as a job as a preparation for next year. Remember, the garden is for your enjoyment so have fun.


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