Well this past week has been very hot and many of our plants have shown certain types of stresses such as droopy leaves or fungus diseases. Some plants will respond well to a little water and others may need to be sprayed with a fungicide. Because it is so hot to work in the sun let me take you into the shade of a tree where the temperatures are a little cooler and give you a few ideas of things that you can do to help your shade loving plants. This week I would like to talk to you about your azaleas and what you need to do to prepare them for their blooming season in the early spring.
Azaleas need to be pruned now to develop thicker plants and more blossoms for the spring. The usual end date for pruning azaleas is right around the 4thof July. Those of you that wait too long to prune may limit the number of blossoms you will get. Pruning does two things for the plant. First, pruning will give you a compact plant which is properly shaped for your landscape and give you many blossoms and second, pruning helps you get rid of old, diseased, or dead wood within the plant. The second part is the most important.
If your azaleas are overgrown or have not been pruned for years you may see long branches or dead wood within the plant that produce few flowers or take away from the beauty of the plant. Long branches that do not have any lateral branching do little to produce additional flowers. These branches should be removed from the plant in stages. Optimal pruning methods require that no more than one third of a branch be pruned at any one time. This pruning should be done early in the year right after the plant has finished blooming. Most azaleas finish blooming in mid February. I recommend you to start pruning this growth back in March and then wait a month or month and a half then prune another one third of the branch. Finish pruning by July 4th as stated above.
If you have been pruning and following the instructions I have laid out above then this week should be the last time you prune. Make sure that you prune out all dead, broken, and diseased branches. These branches should be cut back to the base of the plant. By cutting these branches back to the ground you will encourage new stems to develop. Branches which have been reduced in size break the apical dominance of that branch. This will help encourage new growth to form from the advantageous (dormant) buds on the branch. Once the tip of the branch is cut off, new branches are allowed to form which helps the plant to fill in. The new growth you see this year will produce the blossoms you get next spring.
Many azaleas are left to grow year after year with little or no care. This may cause problems as the branches on the top of the plant grow too long and they cover the branches below them. When you prune your plants be sure to prune the top of the plant back further then the base of the plant. Think about a pyramid shape, large on the bottom and small on the top. This will give you the best shape and better growth habits as time goes by. When you think you have pruned your plants back enough to meet the height requirements you are looking for and the shape I mentioned above, stop. You can always come back at a later time and trim not prune your plant to keep this shape. Make sure to remove the clippings from in and around the plant and put them into the compost bin.
Now that you have had a chance to get inside your azalea plants through pruning many of you have probably noticed leaves that are just not as green as they could be. Leaves that are spotted or have a silver-gray look to the leaf may be suffering from lace bugs. Lace bugs are hard to see because of their translucent wings and because they are very small. But there is a tell tale sign you should be looking for. Turn the leaf over and look at the underside of the leaf. If you see little black spots on the bottom of the leaf then this is a sure sign of lace bug infestation.
Lace bugs feed on the leaf by piercing the leaf and sucking the plant juices. As they feed they defecate on the bottom of the leaf causing these black spots. Most of the damage you will see is on the upper side of the leaf and this is where you will see the mottling or stippled looking areas. If you have seen this while pruning your plants this insect problem will need to be controlled. There are two products homeowners can use to remedy this problem.
The first product you will need is Bifenthrin or Talstar. This product can mixed with water in a pump up sprayer and sprayed directly on the upper and lower plant surfaces at ten day intervals until control is established. The second product is Bayer Advance Twelve Month Tree and Shrub Care. This granular material is neither cheap nor fast acting but it is systemic and is slowly taken up by the plant over time and carries a residual which will protect your plants for the rest of the season. Just read the label then sprinkle the desired amount of material on the ground around the plant and water in. As I said this will not kill the insects for at least thirty days but it will last for at least six to eight months.
Remember, if you are thinking about planting new azaleas or if you already have an azalea you need to make sure they are planted in the right location. Azaleas need to be in the shade for them to thrive. Morning sun is ok but if you have plants that get afternoon sun or direct sun your plants will not thrive and possibly die. Be sure to mulch your plants with good pine bark mulch. The smaller pine bark nuggets versus the larger nuggets work best for me. You will also receive the added benefit of lowered pH as they decay. Be sure to water your plants regularly to maintain a moist growing environment.
Azaleas also want an acid type soil. Soil pH around 5.5 to 6.5 should be fine for azaleas to perform well. If your pH is too high try using and acid forming fertilizer in small amounts monthly. Many local nurseries sell Azalea/Camellia fertilizers which help to stabilize pH if used often. Micro-nutrients or products like Essential Micro-Nutrients should be sprayed on azaleas at least twice per year to help them maintain the deep green color especially in high pH soils. If you have tried to lower the pH around your plants and still have not had any luck I would like to share a trick I learned awhile ago with you.
Let us say that you have several plants in the garden which were planted in alkaline soils but the plants are already grown. What you need to do is to get yourself a posthole digger and dig holes about one foot deep around your plants. Remove the soil from the hole and place this in other areas of the garden then replace this soil with a good potting soil made of peat and perlite being sure to tamp the soil down when finished. Add water to settle the new soil in the holes you just dug then mulch over the top. What this will do is essentially add organic matter to the soil surrounding your plants and this will help to amend the pH around your acid loving plants. Your plants will put out new roots into this new soil and rejuvenate your plants over time. This may take a little effort but the results will please you.
I hope your time working in the shade this week will help to cool you off. Azaleas can be a rewarding experience for you come springtime so get busy you only have a couple weeks left to finish pruning! Good Luck and Remember, without plants, we would not be here.