Monday, November 30, 2009

I love my job

While scouting Dudley Nurseries in Thomson, Georgia last Wednesday and full from a plate of fried turkey (thanks for lunch, y'all!), I took a few minutes to be thankful for the wonderful opportunity I have to work with great people at beautiful nurseries.

I'm one of the lucky people in this world that truly loves what they do for a living. When it's icy and windy or hot and muggy, I may question my decision to become a horticulturist.....but most of the time I'm happy as a lark.

After all, not many people get to stand in a greenhouse full of Fragrant Tea Olives (Osmanthus fragrans) that are in full bloom. If you've ever smelled one Tea Olive, then you'd know that over a hundred in an enclosed greenhouse will send you over the moon:
And the fragrance of Mahonia coupled with the glowing yellow flowers will make you pause for a moment in gratitude:
Lastly, everyone always asks what is my favorite flower. This time of year, it has to be Camellia. When the Camellias are in bloom, I get to wander through greenhouses and shade frames surrounded by these flowering shrubs.

Look at this Camellia japonica 'Pink Icicle'. The flowers are absolutely amazing. That pink flower set against a dark Charleston-green leaf is stunning. It has been my favorite cultivar for the last two years.
Happy Thanksgiving!

Monday, November 23, 2009

Tried and True: 'Mine No Yuki' Camellia

Can you imagine a more heavenly sight? On my way from Goldsboro to Charlotte last week I drove past this row of Sasanqua Camellias, turned my car around and stopped to admire. Each shrub is about 6-7 feet high and wide, collectively making an impressive display.

The skirt of petals surrounding each plant adds to the beauty, like a dusting of snow. The flowers of Camellia sasanqua "shatter" into individual petals as they fall from the stems (alternatively, Camellia japonica flowers stay whole).
This cultivar, 'Mine No Yuki,' was selected in the 19th century and the name literally translates to 'Snow on the Mountain.' The white peony-form flowers occur in late fall.

I love this plant.

Thursday, November 19, 2009

Nursery Note: Southern Red Mites are back

If you have a nursery and you are growing Japanese Hollies, Azaleas, Japanese Camellias or Magnolias, scout for Southern Red Mites.

They are easy to manage if they are caught early. If you wait, they can cause leaf damage and defoliation.

If you are planning on covering these crops with frost blanket or plastic through the winter, make sure that you have properly managed the mites before you cover the plants.


Tuesday, November 17, 2009

Tar Spot on Maple

I love when I find this disease on Red Maple (Acer rubrum).
It doesn't show up until late summer or early fall and it usually only affects a small portion of the leaves. But the spots are large and very distinctive- and they look like tar, hence the common name.

The fungus is Rhytisma acerinum. The specific epithet indicates that the fungus will only infect the leaves of Maple.

When you run your fingers over the leaf, it feels rubbery, as if a dollop of tar dried on the leaf.

Tar Spot can cause premature defoliation, but unless the infection is bad you won't notice.

If your Maple has this disease, the best way to manage it is to rake up the leaves in the fall so they can't cause reinfection the next year. I wouldn't bother unless the trees are being grown for sale.

Wow, right?

Monday, November 16, 2009

Boron Toxicity

We've got an interesting water situation in certain areas of the Lowcountry- excess boron. It was a surprising discovery for me and it took me a long time to figure out. When a landscape is being irrigated from a municipal source, you don't expect a toxicity I never tested.

Well, finally I did. And as it turned out, the aquifer that a certain municipality pulls water from has high boron levels (it is safe for human consumption) . I have found excessive boron in the well and municipal water in Mount Pleasant, Meggett, Edisto and John's Island.

Boron toxicity is fairly easy to diagnose, but it requires a water or foliar test for confirmation.

1. It occurs on the older growth. It takes a while for the element to accumulate in the leaves, so only the older leaves will show injury.

See how the new growth on these Sago Palms is unaffected? This is a typical injury pattern:

2. A marginal "burn" shows up on the leaves of dicots, while a "tip dieback" happens on monocots. The excessive boron accumulates at the very ends of the leaf veins. In a monocot, the veins run parallel and straight to the tips of the leaves. A good example is shown on 'Evergreen Giant' Liriope:It can also be seen at the tips of palms, like this Windmill Palm (Trachycarpus fortunei):
When a dicot like a Hydrangea is suffering from excessive boron in the water, the edges become burned. The necrosis will sometimes look wavy:
Magnolia is extremely sensitive to high boron levels and the injury is very distinctive. In fact, I commonly use this species as my "indicator plant" in a landscape if I suspect high boron.3. It generally doesn't persist in the soil. If the pH is high or there is a lot of calcium in the soil, boron can be bound to the soil. But generally, boron easily leaches from the soil profile. Once the contaminated water is removed as the irrigation source, the plants will recover.

4. Contaminated soil and certain fertilizers can be responsible for excessive boron levels. In my experience, this has never been the source, but it should not be overlooked. If you have fertilized with potassium chloride or amended the soil with marine sediment or animal manure, this may be the cause of the toxicity.

5. Some plants are more sensitive than others. Magnolia, Hydrangea, Palm, Liriope, Cycads and Viburnum show substantial leaf burn. Other plants, like Fatsia and some Camellia cultivars become slightly "off color", but don't have distinctive symptoms. And then there are a few species like Ligustrum and Cleyera (Ternstroemia gymnanthera) that don't seem to be affected at all.

The take-home message is that soil and water tests are a good idea- they eliminate a lot of guess work. As you can imagine, boron toxicity is often mistaken for drought or fertilizer burn.

If the tests confirm that boron is to blame, the best option you have is to limit irrigation. Turn off the irrigation system in the dormant season and run it no more than once per week during the summer.

Use a rain barrel to collect rain water for supplemental irrigation (this is very important for house plants).

Thursday, November 12, 2009

Not about plants

I've been missing my grandmother, Mary Jo, so much...and with Thanksgiving coming up, I've got a lump in my throat thinking about celebrating a holiday with the matriarch of my family gone.

Well, last week, I went to Florida for a meeting concerning the development of a USDA Specialty Crops Research Initiative (SCRI) grant. On my way home, I stopped for the night at my family's farmhouse in Mystic, Georgia. It serves as a rustic weekend retreat and I felt that a night alone in the country would do me some good.
Of course, everything in the house reminded me of my grandmother. I hadn't been to South Georgia in years, but it was just as I had remembered. That night, I saw a short note on the fireplace mantel in Mary Jo's handwriting. Broke my heart!
Naturally, I went through every drawer and closet that evening. In the kitchen I found the instructions my grandfather wrote concerning the opening-and-closing of the house. I love the is so telling of their personalities.
Grandpa was always so orderly and practical. And Mary Jo just loved a good fire.

Wednesday, November 11, 2009

Love this lawn

A lawn is so tricky. It is often the element that pulls the entire landscape together....or tears it apart.

Like a wine stain on an area rug, a less-than-perfect lawn distracts the eye. Even if every other part of the landscape is gorgeous, a dead spot in the lawn will command all of the attention.

St. Augustine, the lawn of choice in the Lowcountry, can be a total nightmare to maintain. The list of pests is long, with Brown Patch and Chinch Bugs causing the most damage.

Plus, we have come to think of St. Augustine as "shade-loving" rather than "shade-tolerant." While it will take some shade, it prefers the sun.....yet people are always shocked with the grass under the deep shade of Live Oaks is thin and underwhelming.

My new grass choice for this area is 'Zeon' Zoysia. Prepare to be wowed:

This lawn, installed by Islandscape Landscaping, is perfection. It is lush, thick and wonderful. If you did a survey of landscape professionals in the area, they'd choose this grass as their preferred selection.

Low pest pressure, some shade tolerance, and island-friendly (this Glen Gardner-designed landscape is on Sullivan's Island), 'Zeon' Zoysia is worth the extra cost.

And want to know the best part? Chinch bugs aren't pests of 'Zeon' Zoysia. I'm sold.

Monday, November 9, 2009

Plant Pest: Cast-Iron Plant Scale

Cast-Iron Plant (Aspidistra elatior) is one of those plants that you don't expect to have any problems. It can grow in areas of deep shade, drought and poor soils, filling a very specific niche in the garden.

Over the last couple of years, I have seen an increase of scale on this species- both in nurseries and landscapes. And it seems to reproduce and establish quickly. This brown insect covers the leaves like braille and is easily detected.

Don't use Horticultural Oil on Cast-Iron plant because it can be absorbed by the leaves and result in a water-soaked mottling.

The best management is to remove any leaves that have scale.


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