Sometimes people report to me that their plants seem to die one at a time. They report that they have watered them and mulched them and followed instructions to the best of their abilities. They need help. when plants die one at a time and in groups there is always a problem. We both want to know the answer. They don't want to repeat the problem. I don't want them dissatisfied either. Now what is the cause?
Sometimes it can be the mulch. Look for tip burns on plants. Tip burns can be the result of esterification of volatiles in cedar mulches. If the mulch had not sufficiently aged before being used as a mulch, this could be the problem. If it appears to continue, I'd suggest that you remove the mulch. You can use it next year so stockpile it, then reuse it again. You must be able to address problems before the plant declines to the point where it is stunted or doomed.
Mulch can act as a barrier to air flow to the root zone. Thus limit the amount of mulch. Remember that mulch is like aspirin. One or two (inches or tablets) is what the doc recommends. If you use 10 or 15 you too may die. More is not always better.
Poor quality mulches can also contain plant pathogens. Well composted mulches that have a heat history should contain less pathogens. For this reason I try to use mulch sparingly.
Tips on Growing Acid Loving Plants
Growing azaleas, rhododendrons, blueberries, holly, pieris, heather, and other plants that love acidic and organics soils.
One of my fond memories of being 12 was catching my first shad. Each spring the shad migrate up the Delaware River to end their life long journey to spawn. Their migration is like clockwork, arriving exactly on time, like the swallows of Capistrano each year. In many ways so are the flowers and buds on plants. I remember my shad and the picture of this trophy. I was standing next to a large azalea in full bloom. Each year I would see the blooms on that azalea and know that as they swelled so the shad were approaching. Thus I came to associate the blooms of azaleas with it's time to go fishing. How smart and lucky I was. For there are so many varieties and blooming times for azaleas plus some varieties have small second flushes, that I can now say with absolute certainty that, "It's always time to go fishing".
There are so many varieties of azaleas and rhododendrons that experts only estimate their approximate number. There are early bloomers and late season bloomers. Some with large flowers and some with small flowers. Some are scented. There is a spectrum full of colors and sizes. Some are evergreen and some deciduous. Thus azaleas and rhododendrons are shrubs for all seasons. In winter, these plants stand out with large evergreen leaves and bring showy flowers in the spring. Throughout the summer and fall the leaves add pleasing green color to the landscape. The intense flowers of azaleas and rhododendrons make them a popular selection.
If you have difficulty telling an azalea from a rhododendron, stop worrying. Call them all rhododendrons and you will be correct. If you know how to grow a rhododendron, then you can use the same cultural principles in growing blueberries, holly, pieris, heather, and other plants that love acidic and organics soils. Rhododendrons love mild humid climates. Site selection is important. Many people come to us and report that they have had little luck in planting rhododendrons and want to try again. Our suggestion is to first look at your environmental conditions and determine if you should replant. Rhododendrons are found in nature predominately on north to east slopes. Here there is less rapid temperature changes and the drying west and south winds are shielded by natural features. Always protect azaleas and rhododendrons from wind. Plant with barriers in mind. Barriers can be evergreen screens, or buildings or slopes. Evergreen screens can help highlight the blooms. Be mind full that a corner of a building may not offer protection but actually funnel winds by the plants. Rhododendrons actually like filtered light better than shade. If your site is full shade consider a pruning of the overhead trees to allow better light penetration.
The soil that you plant Rhododendrons in should have good drainage. You can run a simple test by digging a six inch hole and filling it with water. If it is not drained in 4-5 hours you need to increase the drainage of the site. Rhododendrons have very small delicate roots. If the soil drains poorly there is probably to much clay. The roots can't penetrate heavy clays. I would suggest a raised bed or a drain tile to carry away the excess water.
It is difficult to improve poor soils to grow rhododendrons without creating other problems. Sometimes trees with surface roots rapidly take over soils that are improved and compete for nutrients. They, after all have a head start on your new plants. It may make sense to raise up a bed a whole foot. This gives improved drainage and allows the new plants more competition free time in getting established. Make sure you have an acidic soil of 5 to 5.5. If you have a large pine tree rake up its needles and use them as both a weed barrier and a pH adjuster. There is no good substitute for quality organic materials being incorporated into your soil. Clay soils are especially enhanced by organics.
Lots of ground pine bark, oak and pine leaf mulches and topsoil mixed well, works much better than peat. Peat will hold water preventing oxygen from filtering to the root zone. Peat can also hold moisture for long periods in the spring and winter. The area that you prepare should be prepared weeks before you plant. This allows the pH to change.
Most of the rhododendrons and azaleas
that we sell are potted. These plants should never be planted so that their stems are below what it was in the pot. Plantings should always be about 2" above the surrounding soil. Water the plant well after planting. Native rhododendrons have very shallow surface roots and have natural mulch and organic debris covering the surface roots. This conserves moisture and minimizes winter injury. You want to mirror the natural conditions so using decomposed pine needles and oak leaves is the best mulch.
A layer of two to four inches is ideal. Keep the layer of mulch away from the stem. The mulch should not be removed. It should be with the plant for all seasons. It is the plants winter blanket. It helps keep the plant from winter leaf scorch. If you want your beds to have designer colors such as red mulch black much, plastic fiber cloth, river pebbles etc., then plant some other plant, because these plants are delicate and conditions must be correct or you will have poor results. I don't recommend any fertilizing of the plants for beginners. If you must add fertilizers make sure it is for acid loving plants.In nature these plants do well with low nutrient levels. Their small surface roots can be easily be hurt by over application of fertilizers. I would use no more than 2 pounds of a 6-10-4 per 100 square feet, but organic matter that is covering the plant should be perfect. Do not fertilize after July 1. Fertilizing after this time may force growth during the winter when the plants should be dormant. The mulch can also act a a natural weed barrier. As it decomposes add more. Fall is the optimum time to make sure you have enough mulch.
Following these recommendations will help you have success in raising these plants.
Do you need help in planning or selecting a tree or shrub? Why not email us a picture of the site and let us give you choices for your landscape? We can also have John Murray our in house designer give you a free landscape plan based on the photo. Just let us know what kind of plants you prefer...Evergreen...Natives...Flowering and he will do the rest.