Bonsai Tonight

Pine needle scale

Posted in Bonsai Development by Jonas Dupuich on November 21, 2014

The pine needle scale can be tricky to spot. Small, white spots are the giveaway.

Pine needle scale

Uh-oh, white spots

If it’s fall or early spring where I live, it’s always what I think it is – pine needle scale. Here’s why they can be tricky to spot. When they grow on the inside surface of a pair of pine needles, they’re all but invisible.

Pine needle scale

A sliver of white is the giveaway

Peeling the needles apart reveals the insect – small white spot with even smaller yellow dot at one end.

Pine needle scale

Pine needle scale

If I’ve spotted them early enough, I’ll find singles or pairs of them on a limited number of needles. If I do nothing about it, a few days later I might find far more.

Pine needle scale

Yuck – more pine needle scales!

The reason I’m not a fan – they can be hard to control. Many of the weaker pesticides have trouble killing scale. I usually start with light-touch approaches and mount increasingly potent assaults as need be. My general approach is the same as it is for any scale:

  • If there are only a few I’ll scrape them off with my fingernail
  • If I have to spray, I’ll start with oils
  • If oils don’t get them under control, I’ll using something more toxic, though I typically avoid this last step as I don’t like using pesticides.

What’s the most important thing to know about treating scale? If at all possible, avoid getting it in the first place. How might one go about reducing the potency and number of infestations?

  • Keep your trees healthy. This includes lots of sunshine, appropriate water and fertilizer and well-draining soil.
  • Don’t give them space to hide. Leaving old leaves or needles in place prevents light and air from reaching the tree’s interior – that’s how scale like it.
  • Use oils on a regular basis. Oil sprays are the least toxic treatment for scale.
  • If you know there are lots of scale in the area or have fought infestations in the past, systemic pesticides are a good bet.

Uncontrolled scale infestations can greatly weaken and even kill bonsai. Be on the lookout for them!

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Decandling – how late is too late?

Posted in Bonsai Development by Jonas Dupuich on October 31, 2014

Getting the timing right when decandling is as much art as science – or so it can seem. While it can be tough to determine the ideal time to decandle a tree upfront, in hindsight it’s usually pretty clear what went right or wrong (see When to Decandle for details).

When the proper time to decandle has come and gone, the options are to put off decandling until the following year or to decandle late and see what happens. As I’m often busy during decandling season, it’s not uncommon for me to decandle pines on the late side, and this year I was more behind than usual. For most of the trees that missed the cutoff, I left the spring growth alone. For a few others, however, I decandled late to see what would happen.

In general, I can decandle healthy young pines in mid-June.

Black pine

Decandled 6/22

Black pine

Summer growth – 10/29

In some cases, I was able to postpone decandling without many consequences. I decandled the pine below two weeks later on July 7.

Young black pine

Decandled 7/6

Black pine - decandled 7/6

Summer growth – 10/29

Possibly giving the tree an extra reason to push, I removed a large, cascading branch when I decandled. The remaining stub is now covered with small buds.

Black pine

Dense growth

With other trees I was less lucky. I decandled the pine below around the same time as the tree above.

Black pine

Summer growth – 10/29

As you can see, no summer shoots appeared. This case is a bit different from the trees above in that it has several large escape branches.

Black pine

Escape branches

Typically, trees with escape branches aren’t decandled as escape branches are designed to encourage vigorous growth and decandling aims to slow down growth. The tree above is a poster child for not decandling trees with escape branches.

Where does the energy that drives summer growth go in these cases? Often it’s diverted into the escape branches.

Young black pine

Decandled July 7

Black pine - decandled 7/6

Summer growth – 10/29

Instead of producing summer shoots where I decandled, the tree produced summer shoots on the escape branch. The branches I cut, meanwhile, set plenty of buds for next year.

Black pine

Little summer growth

Strong buds

Healthy buds for next year

Of course, I decandled the above pine on the late side – July 7. I decandled a similar pine with a large escape branch that is twice its age – 20 years old instead of 10 years old – a month earlier. This tree came out fine.

Black pine - after decandling

Decandled June 7

Black pine - decandled 6/7

Summer growth – 10/29

Summer buds

Posted in Bonsai Development by Jonas Dupuich on July 25, 2014

When decandling pines throughout decandling season – late spring and early summer where I live – at any given time one can find summer buds at many different stages of development. The most recently decandled trees in my garden are barely showing signs of summer growth, while some of the first trees I decandled now have quite large shoots.

Some of these shoots sprang from adventitious buds, others from needle buds. I typically decandle pines to stimulate adventitious buds – the buds that emerge from the stub left behind after making the cut.

Adventitious buds

Adventitious buds

Needle buds usually show up after decandling when pines are extra vigorous. Needle buds are new shoots that emerge between needles.

Needle buds

Needle bud

Needle buds

Needle buds flanking an apical bud

Removing the most vigorous spring shoots can yield a profusion of buds.

Summer buds

Profusion of buds

Rather than thin the buds at this stage, I’ll leave them alone and consider removing the entire branch in fall to slow down growth.

Summer buds

Lots of summer growth

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Of red pines and black pines

Posted in Bonsai Development by Jonas Dupuich on July 22, 2014

I’ve found that mature red and black pines can sometimes be hard to tell apart. Leaf character and bark can vary wildly from specimen to specimen and many trees exhibit qualities associated with both varieties. Younger trees, however, are generally easy to distinguish. The black pines I’ve grown typically have straight, sturdy needles while the red pines frequently have needles that are less sturdy and less straight.

1-1/2 year-old pines

 1-1/2 year old black pine and red pine

The young black pines in my garden typically have darker green foliage than the young red pines, though I often see the opposite in older specimens.

2-1/2 year-old pines

2-1/2 year old black pine and red pine

Needle growth often appears more compact in black pines than in red pines.

3-1/2 year-old pines

3-1/2 year-old black pine and red pine

Much of this difference disappears when the trees are decandled, but when left alone, the varieties can often be distinguished by silhouette alone.

3-1/2 year-old pines

Black and red pines

One of the best ways to distinguish the varieties is to check bud color. Red pine buds are typically red.

Red pine buds

Red pine buds

Black pine buds are, counterintuitively, white.

Black pine buds

Black pine buds

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