Extending the zone.

2 replies
Hello, The local nurseries carry plants that technically are not suitable for the Los Angeles area. Question: If the nursery has these trees on full sun and they look healthy, Is it proper to assume that they shall be fine planted in the ground? They say yes. Plants such as Japanese Maples, Mugo Pines, Pinus Densiflora Tanyosho and some others. Is it because our summer temperatures are mid 80's? Today's high is 70 degrees. What is your opinion. Thanks.


Daniel Spear

Remember caveat emptor? Buyer beware. They will also want to sell you “soil amendments” that will ruin your soil and kill your conifers. Just because they sell a plant after a cold winter growing in Oregon doesn’t mean it will grow in LA. There are several challenges, but sometimes things will grow well for a time way out of their zone. Consider soil pH, water pH and high chlorine, typical relative humidity, Santa Ana winds, but the biggest hurdle is lack of winter chill. These plants probably need 500 hours plus of 45 degrees to 32 degrees to properly go dormant and thrive. Over 55 degrees takes away hours, so a typical LA winter day at 75-80 degrees looses chill. Japanese weather is high humidity, hot summers, cold winters, and plentiful rain. It is really difficult to mimic those conditions in your LA garden. Do your best to address these challenges and careful siting in your garden will allow some zone pushing, but it’s a high risk/high dollar experiment.


Thanks for your comments.

I purchased a 15-gallon 'Red Dragon' Japanese maple back in January and is growing. It is still in the container and I am planning to plant it in the ground around the end of October. I am letting the maple tree get acclimated to our local weather. It will be on the east side of my house so it will be shady after 1 pm.

In April I planted a Cupressus arizonica 'Blue Ice' and it has grown 2 inches already! I only paid $25 for a five gallon plant. I think that zone 9 plants do thrive in this area, as you know there are many microclimates along the California coast.

Thanks for the information, I will keep you guys posted.