Flowering Freeway median plants in California

Question from Laura:
A relative driving north from Sacramento toward Reading called me, an Ohio Master Gardener, to ask if I knew what shrub might be planted in the median of U.S. 5 for many, many miles.  I don’t.  There are several hues, apparently: possibly pink, red, white, maybe purple.  Can you enlighten us?  If you have an answer, thank you.

Answer from Pat:
I have not recently driven the road between Reading and Sacramento. However, here are some of the plants that have been introduced recently for highway planting and are often used for freeway median planting by Cal Trans:

Meilland disease-resistant and pest-resistant rose shrubs developed in France especially for highways include ‘Fire’ (red), ‘Ice’ (white), ‘Magic’ (hot pink), and ‘Pink’ (pastel pink). My guess is these are what your relative saw since I’ve seen them also and found them eye-catching. We are seeing ever more of these roses on highways and it’s a bit of a surprise since one doesn’t think of roses as being an easy plant and we also know roses need regular water. It turns out, however, that these varieties are easy to grow, don’t require a lot of special care, and are especially colorful and pleasing when ornamenting medians and banks on crowded highways near or in cities where large numbers of motorists can enjoy the sight.

Also often planted along freeways, especially in the Bay Area, is bright or deep royal blue plumbago auriculata. (I would guess the variety they are using is one of the improved varieties, like ‘Royal Cape’ or ‘Imperial Blue’. ) Plumbago blooms its head off for most of the year and is drought-resistant once established. I have noticed these plants near to towns and especially in the Bay Area. This is a tender plant that cannot be grown in Ohio unless it be in a house, conservatory or greenhouse.

For many years in warmer zones one has seen many miles of oleander (Nerium oleander) blooming for many months in freeway medians in warm zones but winter frost can hit it up north. Also there is a pest called the glassy-winged sharpshooter that has caused a lot of problems with oleanders. All parts of oleander are poisonous but that doesn’t matter in a median plant and its height (6 feet) and fragrance together with dense foliage of long green pointed leaves, make it a good, drought-resistant barrier plant. Special machines are used to hedge it after bloom. Oleander flowers massively spring through fall in shades of pink, white, and red.

Additionally, native plants such as blue California lilac (Ceonothus) are planted in some areas. In inland areas that get very hot and dry, Texas ranger (Leucophyllum frutescens) is one of the best and toughest plants. It provides long bloom on attractive grayish foliage in hot, dry, desert-like conditions and it’s hardy down to 12 degrees Fahrenheit. Another purple plant one often sees along highways is Lantana montevidensis. This also has lavender or purple flowers and is long blooming, drought-resistant, carefree, and easy to grow, but a hard frost will damage it.

Comments

  1. I lived in Sacramento area all my life as a child and the plant that is used is Oleander.

  2. Finally I found out and I now remember my sister telling me they were OLEANDERS. The name just wouldn’t come to mind and my sister is no longer living.
    THANK YOU THANK YOU

    • Thanks for writing. Oleander is one of the plants I mentioned as a possibility in frost-free zones. There are miles and miles of it, growing in center medians in California, even today despite the problem with the glassy-winged sharpshooter which is killing some of them.

  3. Noelle Robbins

    I am particularly interested in the abundant blue flowering plants alongside the freeways in the SF Bay Area. Lots of green leaves and small nice blue flowers.
    I figure if they can survive there, they can survive in my yard. Are those the plumbago auriculata?

  4. I want to emphasize that oleanders are poisonous. They should not be planted where pets, livestock, or children can get at them. I’ve seen horses die from ingesting oleanders. One reason oleanders were planted by the freeways is that most (all?) deer won’t eat it.

    • Thank you for this good comment and informative note. Since glassy-winged sharp-shooters began killing oleanders with virus disease, they are no longer the perfect median plant for freeways that they once were. Besides their deer-proof quality, other virtues of oleanders included, cleanliness, uniformity, long bloom season, and ease of maintenance—(Annual pruning was done by a sort of massive mowing machine). And prior to the advent of the glassy-winged sharpshooter, they were virtually pest free.

      • I just wanted to mention that oleander is so toxic that there are reasons to think it creates toxic honey by honeybees. Also reason to think it may kill honeybees.

        • Thank you for your comment. Yes, oleander is extremely poisonous. In the area where I live, honeybees are wise enough to shun oleander. Perhaps there are enough other flowers for them to visit. Regarding the toxic qualities of oleander, many years ago when burning was allowed, cities and newspapers reminded folks not burn oleander since the smoke is also toxic and a newspaper story related the cautionary news that some un-knowing people had cooked hot dogs on the sticks and all were poisoned. One hopes they lived to tell the tale.

  5. Sally Mitchell

    Where can I buy the highway rose shrubs blooming now?

  6. Maria Perez-Garcia

    Good Evening;
    I just came back from Fresno Area. Driving home on Highway 99 I saw beautiful bright Yellow & Orange flowers along the center of both sides of Freeways and th sides as well. I would like to know what is the name of that ground cover. Feb. 2015. I will need to know asap. can you pls email me back? I would appreciate it. Thank you

    • What does “and amp” stand for? I have asked other people who write me on this blog and use that term but cannot find the meaning on the internet. Please, please, be a kind reader. Please write me back and explain, since I am quickly answering your question as you want and few people will know this answer that I am providing to you. Thanks! I have not driven back from Fresno so I don’t know for sure what these flowers are, but I sure can make an educated guess. Since these flowers struck you so strongly I am imagining they are extremely spectacular. This makes me think they are very likely a type of winter-and early-spring flower that comes from the African Veldt, often called “African daisies and sometimes called “Cape marigold”, but other things are given similar common names as well. Their botanical name is Dimorphotheca aurantiaca. This is the only way to make sure you are getting seeds of this plant! Make a note of the name so you will not forget. They are grown from seeds planted in fall that bloom in late winter and early spring after rains. Once planted and if not overgrown and hidden by grasses or other weeds, they will come back every year. Fortunately, Caltrans spreads these seeds. November is the time to plant them. They need full sun and may close on dull days.

      • My business partner, Loren, who posts my answers to questions on our blog, provided me with the following explanation of what “and amp” means and now I understand why no one ever writes me back to explain. They, like you, never included the word “and amp” in their letter so my question must have totally confused them. It turns out that “and amp” is a software glitch, much the same as when someone puts a smiley face into an email and, instead of a smiley face, the recipient sees a symbol similar to but not exactly the same as the letter J. Here (below) is the explanation that Loren wrote: “The ‘&amp’ is the computer-generated character set for the “&” character. Somewhere along the line when either the reader submitted the comment or when it was submitted it was not converted by the computer and/or software.” (Thank you, Loren, for providing an answer to my question! At last I understand.) Please forgive me, Maria, for asking me to explain something that you certainly did not write and, by the way, many thanks for writing me with your question. I hope my answer arrived in time to be of help.

  7. Also reason to think it may kill honeybees.

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