Q. What’s happening to my Spring Bouquet (Viburnum tinus)? It has bloomed beautifully in the Spring for
several years (including this past Spring), but many of the leaves are turning
brown, and appear to be burnt. I didn’t
see any evidence of spider mites or other pests. I checked the drippers, and it is getting
sufficient water.
A. Spring Bouquet is the marketing name given to the
compact form of a flowering shrub found in the nursery trade in California. Technically
this group of shrubs are called Laurustinus so let’s just call it Spring
Bouquet viburnum. It’s gotten some tracking in the Mojave Desert mostly from
people moving here from California. It’s not a desert plant but it comes from
the dry Mediterranean area so think rosemary, oleander, Laurel, junipers, and
cypresses like Italian Cypress. Like other Mediterranean plants it’s mesic in
its water use so plant it in soil amended with compost and it may not
like being surrounded by rock after a few years down the road. It grows best on the east or north side of a
home. You will take more chances growing it on the south or west sides in a sunny
location, but it may do okay in the shade of a tree during the hot afternoons and
surrounded by other plants. It will not like rock on the soil surface as it
gets older.
Like
other Mediterranean plants the biggest disease problems are root rots from
watering too often or poor water drainage. Viburnum like yours gets aphids and
thrips in the spring. In the heat of the summer, it may get spider mites and
thrips damage may continue. So, you are right for checking or spider mites when
summer temperatures arrive. If spider mites are problems the leaves appear
dusty and oftentimes light webbing can be seen.
 |
| This webbing from spider mites (why do you think they are called spider…mites…?) on tomato but if they are spider…mites…then you will see webbing on your plant as well. |
However,
the usual problem is planting them in hot bright locations and then surrounding
them with rock on the soil surface. The soil amendments last for a couple of
years but they slowly dissolve into desert soil over the next 3 to 5 years and
the plants start getting burnt edges around the leaves.
Before
buying an insecticide look at it at about 2 PM. Is the location where it’s
planted hot and very sunny? Is the plant surrounded by rock on the soil surface?
If the answer is yes to both of those questions, then it’s probably a location
problem combined with a soil problem and not spider mites. Nurse it through the
summer and in the fall rake back the rock, amend the soil with compost and
cover as much of the area with woodchips as you can.
Try the paper test for detecting mites because they are so small