Rosemary likes infrequent Waterings Or There Will Be Problems

Q. My Rosemarys are dying.  I planted quite a few thinking that I won't have a problem with them.  I lost two already that were planted about five years ago.  I just planted six more this last spring. What is going on? They get enough water and fertilizer.  I am afraid that I'll lose them all. The Rosemarys that died were planted on the east side about two yards away from the house.  They got a hole about 1, 1/2 feet deep and wide with mixed soil. They get sun in the morning and afternoon sun from the west.  The sprinklers go on only four days a week for 10 minutes in the summer, but in the winter I set the clock to go on only twice a week. It could be that there is bad drainage so close to the house. What else should I plant?  I noticed one Rosemary in the front of the house which is the west side, getting dry shoots, which I cut off.

Healthy Rosemary on top picture. Rosemary with problems on the bottom two pictures. The middle picture is most likely a water or drainage problem or possibly salinity.

A. It is possible that it is due to poor drainage but I still think your watering too often in the summer. They should be able to last longer between irrigations.

Posthole digger

Usually the soil surrounding the foundation is compacted for the slab’s stability. You could take a posthole digger and go down two or more feet and backfill this hole with amended soil and replant again.

I would dig a hole 3 to 5 times the diameter of the container you are planting anything in our soil. Three times a week in midsummer might be too often for rosemary unless you have really good drainage. It is not a desert plant but it does not like wet soil.

The soil amendments I am suggesting is really good for any plant, including desert adapted plants so you should be doing this anyway. It is hard for me to recommend something without knowing your needs, the site better and what is available.

The most common reason for Rosemary to die is because the soil stays too wet. You definitely do not want to water this plant daily unless the soil it’s growing in drains water exceedingly well.

The principal reason for the soil staying too wet is a lack of drainage. Typically if soils growing Rosemary stay too wet the roots will develop a disease called root rot and they die and collapse.

Shortly after that you begin to see the top die. Often times you'll see one or two shoots dying and then typically in the heat of the summer the whole plant suddenly dies.

Once the soil gets contaminated with this disease organism other plants susceptible to that disease and placed in that soil might also become affected. Replanting Rosemary in the same soil where it died is not a good idea.

It will like a place in the yard in full sun and hot. It will not like shady areas very much.

The next time you plant Rosemary make sure the soil is thoroughly mixed with compost to a depth of at least 12 inches. Rosemary originates from Mediterranean climates.

Mediterranean climates are characterized by hot and dry summers and cool and wet winters. Rosemary does very well in the heat and can tolerate the cold.