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Monday, March 25, 2013

Pink Leaves on Purple Plum Probably Iron Problem

Iron chlorosis on purple leaf plum
Q. I have two red leaf plum trees both about two years old. They started the year beautifully. One continues to look normal but the other one has all of a sudden taken a turn that bothers me. The leaves are getting pale, pink instead of red and see through-ish. It is a nice full tree yet young. Is it as simple as not enough water or something else? It had a great year last year.

A. It is most likely iron chlorosis. If you want to see if that is the problem try making a few liquid applications of an iron chelate to some leaves using a spray bottle to see if this turns them dark purple (I am assuming you have a purple leaf plum).

            It may take four or five applications with a spray bottle to the same few leaves a couple of days apart since liquid applications to the leaves are not typically as effective as applying it to the soil. Otherwise buy some iron chelate containing the EDDHA chelate and apply it to the soil in a bucket of water and wash it in around the roots.

            You should see it turn dark purple in growth that comes out AFTER you make the application to the soil. This discoloration is also possible if the tree roots are being kept too wet by watering too often or you have poor drainage.

Asparagus Should Be Cut Below the Soil Surface

Q. I have a raised bed (5 x 10 feet) dedicated to asparagus. The yield has been magnificent. However, the plot has gotten so overgrown with old asparagus stumps that I have had to totally remove and replace all the soil because cultivation was impossible. My question is how long can an asparagus garden last without being so impacted that it must be replaced; or, is there a way to deal with spent stumps annually to prevent this problem.

Purple passion asparagus with some rabbit damage. Rabbits love the
higher sugar content of Purple Passion
A. Asparagus rhizomes are normally planted about 12 inches below the soil surface. If started from seed, the seed is planted in a trench and backfilled as the plants grow so that the developing rhizomes are still at about 12 inches deep. 
Asparagus crown for vegetative propagation. Selecting crowns that
are male will guarantee a male crop. Spears emerge from the top
where the fleshy roots come together

When this is done the spears can be harvested by cutting below the soil surface with a knife so that these "stumps" don't stay on the surface. If you harvest the spears by "snapping" them or breaking them above the soil surface then you will get these woody stumps remaining above the soil surface and they interfere with future harvesting.

So, in short, if you can harvest by slicing with your knife an inch or so below the surface I think this will stop your "stump" problem. The woody part is cut off after harvesting during food preparation. The woody part should compost fairly easily.
Snapping off spears will cause the spear to break just above the woody portion. Nice
for the kitchen but leaves a "stubble" behind in the asparagus bed

Recent research has pointed out that asparagus spears can be harvested anytime the spears are pencil diameter or larger five inches above the soil level. Smaller spears should be left to grow into fernlike growth to replenish the roots for upcoming seasons. The plant is still expanding its root storage system and excessive removal of spears weakens the plants. However, there is a market that has emerged utilizing these very thin spears.

In commercial operations all spears are harvested cleaning the entire bed and spears are allowed to grow to ferns only after the harvest period. An asparagus plant will yield an average of 8 to 12 spears per year before the roots need to be replenished by letting the spears develop into ferns.
Harvest spears by cutting or snapping. To cut a spear, run a knife into the soil at the base of the spear and carefully sever it. Because the spear cuts below the point where fiber develops, it becomes necessary to remove the fibrous base from the tender stalk. Most homeowners and some small scale growers prefer to snap the spears. This eliminates any woody growth on the harvested spears. This does however leave a "stubble" on the surface that can make harvesting more difficult.

To snap a spear, grasp it near the base and bend it toward the ground. The spear breaks at the lowest point where it is free of fiber. Stalk diameter is not a good indicator of proper maturity and associated tenderness. Hydrocooling, or plunging freshly harvested spears into cool, clean water is strongly recommended.
Commercially, asparagus is graded by class (US Number One and US Number Two which are based on straightness and head compactness) and by diameter 5 inches from the tip (see table) according to USDA standards for canning asparagus.

Stems of Beans Devoured at the Base

Beans planted in cool soils can get collar rot or get devoured by cutworms
Q. I found a couple of beans in my garden that have been devoured at the base. Could it be some sort of soil born larva or possibly a virus?  Any ideas would be helpful. I did find one small white worm about a half of a centimeter long near the root about an inch away. 
A. It could be a couple of things. First, with cool weather and cool soils it might be collar rot disease that rots the stem at soil level. This will happen if you plant beans too early in cold soils. Some varieties of beans are more susceptible to this than others.
Most likely cutworm damage
            The first indicator is that some plants appear stunted and grow poorly.  I usually end up removing these plants and hope the weather warms up. 

            The other problem can be cutworms.  You should be spraying or dusting the soil surface around these plants with either Dipel or Thuricide, an organic pesticide.  This is the time of year you should be doing that anyway for a variety of pests in the vegetable garden.

Poisonous Plants: Dose Makes the Poison

Q. I have a volunteer gopher plant in my front yard that I nurtured into a bush.  I noticed that something is eating its leaves.  We have a great deal of rabbits in our area. Can it be rabbits?  I thought that the Gopher plant was poisonous even to rabbits.

A. I assume we are thinking of the same plant. It is a euphorbia with white latex sap coming from a damaged stem, similar to the white sap you see in poinsettia which is also a euphorbia. We tend to react to poisonous plants with fear but there are degrees of toxicity when we call something poisonous.

            I watched a professor of mine in floriculture on television take a poinsettia leaf and eat it. He didn’t die or even get sick. He was demonstrating that the plant is toxic but it is the “dose that makes the poison”. If he had eaten many leaves the story would be different. Even table salt is poisonous if we eat enough of it.

            So it is possible for an animal to eat “poisonous” plants and survive. I have heard that some livestock will eat gopher plant in the range with no ill effects. They just don’t eat a lot of it and only when browsing is poor. Just like us, animals like to eat things that taste good.

Sunday, March 24, 2013

Hybrid Bermudagrass Lawn Needs the Bumps Gone

Q. My hybrid bermudagrass lawn is flat and 30'x40', yet it seems bumpy when I mow. Can I get it as flat and smooth as a putting green? Should I top dress with sand or something else? If so, what and where do I buy the material, and how do I spread it? I do not overseed in the winter, thus it's dormant now.

Hybrid bermudagrass makes a beautiful soil cover but does require
work to keep it like this
A. You can do a lot of damage to hybrid Bermuda and it will come back but you should do this when it gets hot, not now. You can level it by taking the high spots out with a straight-nosed shovel, you can fill in low spots with soil (not sand, but something similar to the soil you have now).

Once you get these highs and low spots rectified, then this putting green (if that is what you want to do with it) will never have the same type of ball roll as a putting green because it is not built the same way. The best putting greens are constructed along very specific engineering specifics called the USGA Greens Section constructions specifications.

In golf course terminology you have what is called a "push-up green", one that is made inexpensively from the local soils. These work just fine but will not give you the “feel” of the Augusta National.

Aerator for turfgrass.
Sorry but I dont remember where I got this years ago.
If you aerate lawns in LV, let me know.
Once you have your area level you should then start to aerate, fertilize and topdress your green on a regular basis. Topdressing can be done by hand with a shove with a little practice at "throwing" it.

I would look at sourcing stuff like this from sand and gravel company. Sand is used a lot because it is smaller and won't interfere with ball roll and it is inexpensive. For professionals they would select sand similar to the sand used for constructing it.

If you don't have one, you will need a greens-type mower (usually around $600or so for the inexpensive type or frequently you can find one used from people who have converted to desert landscaping). But this will be a reel-type mower, not the rotary type.

Greens are mowed at about 3/8 inch or thereabouts (bragging rights among superintendents is “how low you can go” with some at ¼ inch). These types of heights mean mowing daily in the summer months. If you let it go and mow it after a week you will not have the same quality. Mowing frequently makes the grass “tight" and helps keep weeds out as well.

Thatch is not just the light brown stuff, its the dark brown peat moss
stuff below it. It is mostly dead stems, not leaf blades
This climate can produce very high quality hybrid bermudagrass. It is similar to Tucson. I would rule out the climate as a problem. If it is flatter than this, then you should fill in the lower spots with soil similar to the soil in the lawn. I would not use pure sand to fill in these low spots.

Bermudagrass will start to have an inferior look if you don’t dethatch the lawn. An advantage of overseeding bermudagrass in the fall is that this process requires dethatching or opening up the turf for better soil and seed contact to improve germination. If the area is small, a hand dethatcher is adequate and gives a great upper body workout.

You would overseed sometime between mid-September and mid-October in our climate. Use high quality perennial ryegrass, not annual rye if you want a high quality winter lawn. Seeding rates are high if you plan on a greens height cut in the winter.

I would use something around 15 pounds of seed per thousand square feet. When you mow close, the grass plants need to be closer together so you have to use a higher seeding rate than it says on the bag.

Aerating is important but if you do not dethatch bermudagrass you will have problems with color, texture and just plain looks of the grass. If you don’t overseed in the fall then you should dethatch it, but earlier so it has a chance to recover and fill in before cold weather hits. I would dethatch any time it is actively growing fast.

Bermudagrass can handle that kind of stress in the heat. Cool season grasses like tall fescue cannot and must be dethatched in the spring or fall; fall is preferable, around mid-September to mid-October. Same time as overseeding (strange how that works).