Herself’s Houston Garden

Sagos are one of the easiest plants to grow, though the growth can be frustratingly painful for some people. Usually a dose of fertilizer or removing the bottom third of the fronds will get the plant pushing out new fronds for you.

This plant has been working away putting out pups at the base last year and it’s getting ready to seed this year.

Yellowing on the outside of older fronds is not a problem and very rarely cause for concern. Just remove older fronds when they turn brown.

Scale can be a problem. Picking scale off a sago is a job for only the most devoted of gardeners. I’d recommend using orange oil. The first symptom of scale is often yellowing leaves. So if you have newer leaves turning yellow, flip them over and check for scale.

If there is no scale and there is yellowing of newer leaves check for fungus. Take a magnifying glass out to your sago and go over the leaves looking for bumps. Fungus can almost always be cured with a fungicide from your local nursery.

If there is no scale and no fungus then you are sitting where I am now. It is most likely a magnesium or nitrogen deficiency. Since this plant is busy making babies and seeds, I’m guessing that is probably the correct answer. I’ll fertilize tomorrow. If a lack of nutrients is the problem, the yellow spots will remain yellow, but new growth will be green.

More information:
Sago Palm, Cycas Revoluta, care and information

There’s been some talk on the Oleandar Page about leaf scorch spreading here from other areas on leaf hopper insects.

But this is a rose bush, in a bed with three other roses who are doing quite well. The markings of leaf scorch are distinctive. If you see a triangle of brown on the end, surrounded by yellow, that’s definitely leaf scorch. The discoloration of the leaf is caused by a lack of water reaching the edges of the leaf. The causes for the lack of water are not so easily identified. This plant looked like it was wilting a few days ago and the wilt has continued to progress.

We’ve had no serious rain for a long time here. ( see Rainfall map for Harris county to find your rainfall totals by day, week, month.. ) We’ve had 3.5″ of rain in 60 days most of it about 60 days ago. It has also been windier than normal here which also dries out the soil and plants. Leaf scorch usually appears during dry, windy spells.

Other causes of leaf scorch are a lack of roots on your plant from root rot ( over watering ) or lack of drainage ( clay soil ); from a wilt disease such as oak wilt; or from a bacteria spread by insects such as the leaf hopper.

If you see this symptom look for insect damage. Leaf hoppers are very tiny insects. Look on the underside of the leaf to find them. Damage from leaf hoppers on your roses will give the leaves a speckled appearance as if you had splattered yellow paint on your rose leaves. Or it may give your roses a tiny white dots all over the tops of the leaves. It will look like you spilled salt on the leaf. If you have the bacterial leaf scorch you will want to remove that plant as soon as possible to prevent the spread to your other plants. Other nearby plants should be sprayed on the underside of the leaves with an insecticide.

Since we have been in a dry, windy spell and the other three bushes in the bed are fine, I’m going to guess I just need to water more. If you are seeing this be sure you have a few inches of mulch around your plants to hold the water in the soil as long as possible.

More information
Leaf scorch of ornamental trees and shrubs
Bacterial leaf scorch

See also:
Tea Roses

I had never heard of nematodes before, I guess that they are not as much of a problem in New England? Down here in Houston they are a problem.

When you bring a plant home, carefully check the roots before planting. Look for knots and swollen areas on the roots. Once you add root knot nematodes to your garden, they are there forever. So it is best not to bring them home. ( University of Ontario has an article with several good pictures ). Be especially sure to check your tomato plants since that is the most likely way you’ll pick them up down here.

Nematodes are microscopic worms some are good, some are bad. The bad ones have a needle like part they use to puncture plant roots. They then inject an enzyme into the root which softens root, then they suck that back out of your plant roots.

You can reduce the number of nematodes in your soil by adding grated orange peel about 1%-5% to your soil. Nematodes must be in damp or wet soil. They die when they dry out, but the eggs live on to reappear when soil gets wet.

When I was outside last month making my first spring pass in the garden I noticed a row of false hollies had leaves all turning yellow and brown. When you see yellow leaves on a plant the very first thing you should do is flip the leaves over and look at the underside. When I flipped the leaves over I found scale. Neem or orange oils are the preferred choices and you can find them at most nurseries. I use orange oil, but in a pinch any oil you have hanging around the kitchen will do just fine. Spray the bottom of the leaves thoroughly.

If only a small part of a plant is effected, prune off that branch and spray the underside of remaining leaves with oil. These plants are totally covered. So if the spray does not work after two weekly applications, I’ll cut them back to the ground and let them start over.

Tea scale was first discovered on tea plants in the early 1900s. Hollies, camellias, tea, olive and citrus plants are all known to be victims. The life cycle is between 45 to 65 days. We can get them year round here in Houston as well as in other warm climate areas. Usually they show up in the spring.

If you have constant problems with scale in your garden you might also consider a systematic pesticide. These are absorbed by the plant through the roots and deliver toxins to the scale. I don’t use systematic pesticides in my garden, but if you are constantly fighting scale you should consider them. They are available at your local plant supply place as well. ( see Control of tea scale using root absorbing systematic insecticides )

About the only good thing you can say about scale is that is doesn’t move. So you know where to find it when you come back with another round of toxins. Scale does have a crawler stage early on when it is first hatched. Once it finds a good location it settles in and forms a hard shell over itself. Almost all the scale you see are female.