Q: We've been in our home for more than seven years, and in the first year, we had a couple Japanese maples and a fruitless plum planted on the north side of our home. About four years ago, we had another variety of maple (with purple leaves) and a magnolia planted along the north side as well. Our side fence along the street where there are several pine trees also is on the north side.
It seems as though all the trees along this side of the house are stunted. The Japanese maple is no more than 6 feet tall. The plum looks the same as it did when it was planted seven years ago. The magnolia grew maybe 2 feet in over three years.
Several shrubs along the north side fare well. But I've tried some laurels, and three have died over the past three years and only one survived.
The trees were planted by landscapers so I thought they would have done a nice job.
Any advice would be appreciated.
– Art Taketa, Roseville A: UC Master Gardener Bill Pierce, said additional details are necessary to provide a specific diagnosis. However, hopefully the following possibilities will assist you.
Construction issues, improper planting, competition and irrigation all could be culprits.
Are you the first owners of a home in a new development? If so, your soil may have some deficiency that is inhibiting plant growth.
In real estate developments, the topsoil is moved back and forth to establish grades and facilitate the building. Some lots, possibly yours, have nothing but nutrient-poor subsoil on them.
Nurseries sell inexpensive soil test kits that will help you determine the amount of nitrogen, phosphorus and potassium. Soil testing firms can test your soil for the presence of the 14 or so minerals needed for plant growth and health.
Another possibility is that the landscape firm planted the trees deeper than they were growing in the containers. This can lead to root and crown rot. The trees kind of "choke" and don't grow.
Remove some of the soil around the crown area on the trunk of each plant to see if you can identify the original soil level when it was in the container. This will be hard to identify after seven years, but if the trees were planted too deeply, you will need to remove soil to relieve the "choking" effect.
Young plants can be replanted so that the crown is approximately 2 inches above grade level. Soil can be added, and the grade sloped away from the crown.
This added soil will promote good drainage, reducing the worry about root and crown rots. Your plants may settle some after you have raised them, but they will still be above grade level.
Heavy clay soil – a problem in many parts of Roseville – may be retarding root growth. The roots may not have grown much beyond the original container site.
Irrigation, either inadequate or excessive, will retard plant growth. To determine if your watering methods are sufficient, you will need to be a "garden detective" and dig in the root zone to verify that water is penetrating approximately 18 inches. Also look for excess standing water.
The north side location may not provide the adequate sun exposure of six hours per day. The pine tree roots could be encroaching on the area.
Visit the Sacramento Tree Foundation website (www.sactree.org) for more information on tree planting and watering techniques.
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