This spring I had asked the group whether tea roses could be dry grown in Mediterranean climates. I had gotten varying responses but the general drift was that they could not be grown reliably without watering in southern California, and Kim/Roseseek said they would be susceptible to sunburn and associated dieback and death, if not given enough water to maintain a full foliage canopy.

Well, looks like Kim was probably right! A study by Robert Mattock Roses at http://www.robertmattockroses.com/ibiza.asp had high hopes for the Tea roses as drought resistant but they failed abysmally. Plants were grown on rainfall only, in an area with similar rainfall to where I landscape in Pomona. They only list the successful roses, of which there are no Teas. Reading their explanation, it seems like the problem for Teas was sunburn although they don't state it explicitly. Successful roses include Rugosas and Wichuriana ramblers. Glad to see my old Mendocino favorite Mme. Alfred Carriere on their list.

If anyone has any comments/suggestions I'd appreciate it, as a rank amateur with a desire to use antique/unusual roses in very dry gardens.

Thanks,

Nate

" shipped from Oxford and planted during late November. The soil had been previously ploughed and rotovated; holes were dug and the bare-root, root -pruned plants let into the holes with a couple of handfuls of local proprietary compost. The plants were heeled in and watered once only. No further irrigation was employed. Straw mulch was employed each summer."

Will they bloom? No. Will they look good? No. A thick mulch would certainly help, as well as all-afternoon shade. Still, why go a whole summer with no flowers?

Is greywater irrigation a possibility?

Since the point of an ornamental plant is to look...ornamental, it seems like shooting yourself in the foot not to water them.

And not just Teas, either. That's why I've been so skeptical of the "Earthkind" Trials, relating to SoCal. TX gets summer rain. Southern California -- not really.

And of course, there's the issue of when they will bloom.

In our increasingly hot summers, NO WATER would mean there would be little or no bloom. Winter -- as long as the rains don't fail -- there would be plenty of bloom, but for a public garden, that's maybe not enough.

Jeri

Hoovb, it all goes back to my design concept...using plants that grow and bloom in winter and then become dormant in summer, which is symbolic of the Mediterranean climate. Why do people accept plants like the Liquidambar, which is completely bare in winter? Probably because it's seasonal changes are comfortingly familiar reminders of colder climates. Plants that go dormant in summer can provide symbolic references to the Mediterranean climate. Maybe most roses look hundrum when they are dormant but some, like Safrano and Madame Lambard, make a good display of hips during their summer dormancy. And if people can enjoy these seasonal changes then it becomes much easier to conserve water.

Thanks for your input,

Nate

You're right -- of course -- And there are many other examples, as well.

I just think it will take a LONG period of education.

Jeri

Ingrid

I don't expect roses to perform with no water whatsoever for that length of time, which is what unirrigated roses would face in my climate. However, I am interested in knowing which roses can get by with an infrequent deep watering, say, a deep watering once a month, or even every third week. By deep watering, I mean 30 minutes of overhead spray. I have a dozen or more established climbers and teas on that program. ( I do give them an extra 10 minute cycle midway between waterings if we get a serious, prolonged heat wave.) Of course they would be happier with more frequent water, but they do okay on that. Note that I reserve this treatment for distant roses on the back fence. The ones up close to the house that I see every day are watered once a week, lush treatment by my standards.

Rosefolly

Thanks Ingrid and Rosefolly.

There are many different ways to celebrate California and the Medit climate--in my designs I show respect for my clients by putting in plants they truly prefer but I always try to reduce water use in different ways--reducing or eliminating lawns by increasing paving, groundcover, etc and using green-looking, drought resistant plants. Roses only need moderate amounts of water to bloom okay, as Rosefolly points out. I think the pragmatic thing to do for private clients is to think in moderation.

Everyone should be able to do what they like with their gardens. My whole point is that winter is thought of as the time for dormancy, when it often should be summer. Most rose gardens are pruned in Jan or Feb, and put out of commission for 2 months, which makes no sense for Tea roses (and some of their derivatives) because that is their natural blooming period, see the plant breeder Franceschi's observation on Rosa gigantea at the URL--the plant's bloom season is in winter in Santa Barbara (he says).

I'm hoping at some point to put in more unusual gardens for people who are receptive to the symbolic use of dormancy and growth to reflect the climate, e. g., rose hips as a dormancy symbol for summer. The beauty of Tea roses is that they are naturally suited to bloom and grow in winter. Why can't we have a long lustrous winter of blooms and just feel natural about our roses going to sleep in summer, albeit with showy hips or with other structural plants to keep up appearances?

I don't mind a short dormant period in late July/August. My roses normally bloom from April - October. This year, I have tons of buds/blooms still, the result of some nice fall rain and moderate temps. The teas are doing especially well now.

Roses tend to be selected for their characteristics when they are actively growing but for very dry gardens you would have to think about their dormant aspect as well, and not use too many that were duds at that point. A different way of thinking about rose gardens, but it's valid.

Or like Melissa you can follow the Mediterranean tradition and surround your rose garden with evergreen hedges in some kind of formal layout. Or shrubs and trees can be used informally, in some kind of composition that is not dependent on the nearby roses. Then the structure and beauty of the garden is carried forward in the dry summer.

Because of all these factors dormancy doesn't have to look ugly. For me, the medit seasonal changes are romantic and something to look forward to--the summer is golden light and plants waiting for the rain; in the late fall the roses wake up with dramatic purple shoots, the winter is long and lustrous and full of bloom.

!!As long as you have an opportunity to plan it out that way!!!! And some medit gardeners like Melissa also have a winter dormancy to contend with.

You are so right! I assisted in my sister's HOA's thoughts of "going native" because they believed "native" meant never watering. What finally got the idea through to those who believed lush, green could be achieved simply by planting "natives" was to point to the dry brush on the hills around them and say, "no water, native". Yes, you can skew the results more toward what you hoped for by careful selection, but very few "natives" look acceptable to modern eyes unless they are frequently groomed and regularly irrigated. Even "ornamentals" such as lavenders, rosemarys, santolinas, salvias, euryops and most other daisy types, look like crap unless they are dead headed, groomed, pruned and kept watered. Otherwise, they look very much like the "native sage brush" all around us on the brown hills here in California.

I just visited Redding to deliver some roses to Lyn. It is very instructive to watch the zone changes as you travel along the state. It is obvious where the rain falls, and where it doesn't. Where there IS rain, things are lush, green, wooded and colorful. Where it doesn't, brown and gray (called fire fodder) predominate. We in the more arid areas can have those results, but that requires irrigation. No depth or type of mulch can substitute for double the rainfall inches, nor for a greater percentage of the year. Thirty-plus inches of rain for nearly half the year makes a tremendous difference when compared to less than half that, mainly delivered in three to four months and very often resulting in tremendous run-off and erosion. Kim

SO VERY TRUE!
And, as our available water supply diminishes, we are going to have to learn to change our ideas about beauty. Where I live, our acquifers are in real jeopardy -- rendering decorative irrigation pretty perilous, long-term. What works where nature provides water isn't going to work here, forever.

I've got a photo of my G-Grandfather's home in TX, taken in 1901. Step-Gramma grew roses, and you can see them, but they are inside a bob-wire fence, and located where dishwater and such could be dumped on them.

Jeri

Well, back to roses: they could be used as adjuncts to the style, in close-in garden spaces where they could be given extra care. As long as the roses showed winter growth then they would "resonate" with the other species.

Kim .... did you notice the change in the native vegetation as you came up the mountain ? That's something I watch for every time I go down the mountain to go shopping.

Smiles,
Lyn

No deer at the SF airport ... 'o)

Smiles,
Lyn

Olivier Filippi's Dry Gardening Handbook helps gardeners decide on plant selection if they want to dry garden in a medit climate (no watering in summer). Plant drought hardiness (though it's complicated) is summed up in a "drought code".

Pomona is rated drought code 5; most roses are rated drought code 3(the lower the number, the less intense the summer drought). Drought code 3 is fairly drought resistant. Drought codes are the same thing as "hydric deficit" in the map. The map shows some cities in California (including Redding (drought code 2), LA, San Diego, etc). The drought code is easy to calculate, send me PM if interested.

I see that Santa Barbara is Deficit 5 -- but our immediate area gets markedly less rainfall than Santa Barbara (pioneers here depending in large part on springs, rather than rainfall) so we're probably Deficit 4, or close to it.

Am I understanding correctly that roses can theoretically withstand a drought-code 3 without irrigation???

I think it would depend in some part on the roses measured. (For instance, we know from experience that most of the Austins show definite stress without ample water ...)

Again, this is of course meaning that they probably won't DIE, rather than that they will be beautiful garden plants after 4 or 5 months without water, right?

Like my Step-Great-Grandmother, we save water in containers, and pour it on the roses -- and that helps.

Jeri

I have a very large, double white Banksiae in the very loose, very dry, un irrigated slope at the southern side of the rear deck which receives direct, full southern sun about 80% of the time. The ONLY "irrigation" it ever receives is either rain or the extremely infrequent hosing off the deck. I cut it off the deck a month ago and it already has a good fifteen feet of "wands" thrown up on to the deck, both from out side it as well as through the openings between the floor boards. Everything on that slope requires watering except that Banksiae and the volunteer black walnuts and peppers. There is a newer terrace which begins about fifteen feet away from that spot, but in the same exposure. It contains seedlings, the Atmore Lamarque, Reve d'Or, and George Washington Richardson. These MUST be deeply watered weekly if temps are in the eighties or above. That blamed Banksiae was planted there 35 years ago, watered weekly its first year, then left to its own devices. The Myrtus communis compacta in that line was well established when the house was bought in 1975. In all that time, it has only received rain and it is nearly six feet tall and much wider. Until I began planting back there last year, only the three existing roses and one crepe myrtle were irrigated and that was weekly (at most) by the gardener who kept the place trimmed and leaves blown off. Otherwise, there is no irrigation system and no one else dragged a hose around to water.

Lili Marleen, a well established plant in 1975 when the house was bought, has Manetii stock escaping from under it. the Lili Marleen was nearly gone, but the Manetii has inch and a half thick canes exploding in all directions which I'm working back so both can be maintained. Manetii made it all these years on weekly watering and rain.

If the wood is hard and dense enough and the root system sufficiently vigorous, it MAY work with weekly supplementation. Softer wooded types or those whose root systems aren't as invasive, are going to struggle terribly, or outright fail. And this is in the Encino Hills where we get more coastal fogs and generally more rain than many hotter, more inland areas.

This is the Wunderground calendar for Historic Lincoln Park in Pomona showing temps and rainfall for the month. I selected it as the elevation is similar to ours here.

http://www.wunderground.com/history/airport/KFUL/2012/11/19/MonthlyHis tory.html#calendar

This is the closest one to here, though it is 200' lower than I am.

http://www.wunderground.com/history/airport/KVNY/2012/11/19/MonthlyHis tory.html#calendar

It might be interesting viewing the historic data for the month as it shows comparative heat and precipitation. I know the performance of many plants here in Encino as well as the Santa Clarita area, where I grew over twelve-hundred roses for over eighteen years. I can well imagine what should be expected from them with little to no irrigation there in Pomona. If you select wisely, plant properly and irrigate sufficiently until they are well established, you might well succeed. But, your selections would be better skewed toward Banksiaes, Fortuniana and deciduous, xerophytic species. They possess the extensive, vigorous root systems, harder wood with greater sunburn resistance, and the ability to suspend their activity sufficiently to withstand the extremes in heat and drought with the least damage. Kim

On the other hand, if we can gather up our damp foggy dew from our roof to the rain gutters and on to the roses, we might both move up to a damper "zone" I am working on cleaning up one area of some of the banana trees that have survived and produced well because they are under the rain gutter. I think I will change the gutter a bit and let some roses enjoy the roof run off. Just a little bit extra water can make a big difference in a plant. Of course having the RIGHT place is the key!

I am also working on a system that mom can dump dish or mop water and have it run under ground and water another bed of roses with out splashing the house etc

He rates roses between drought code 4(Rosa banksiae, as Kim observes, and R. sempervirens) and 2.5 (Rosa brunonii). The majority of roses are drought code 3. Which means in your area you would always have to provide supplemental irrigation for all the species above.

Thanks for all of the information Kim. Aren't the xerophytes like Rosa hemisphaerica, foetida, stellata dormant through the winter? As a designer I'm more interested in the winter active species, e. g., R. minutifolia.

I don't doubt that my climate will fry most roses without watering. The reason that I was so fixated on Teas, though, was because of their ability to go dormant, defoliating upon the drought and waiting for better times. Gertrude Jekyll, speaking of tea roses on the French Riviera: "tea roses...not only bear but enjoy the summer heat and drought, flowering freely in November and December after the autumn rains and pruning" Wouldn't the only problem, in the case of the very-dry grown Tea rose, be sunburn? Which would mean plants should be grown on north facing walls or be provided temporary shade while they were dormant in summer/early fall? Sorry, but I have to ask. And consistent with Gertrude Jekyll's observation, the understock R. odorata has a much stronger ability to go dormant in drought than the other understock types you had mentioned. See attached. I just want to get to the bottom of this--and keep in mind that I don't mind using summer-deciduous plants. I believe Rosa odorata/gigantea are forest plants in their native haunts, which explains the tendency to sunburn.

Kippy, I also always try to think of ways to make things a little moister for plants in dry gardens. I think the drought codes are good because they help us move into the unknown (or previously known and then forgotten) territory of gardening with the rain, but they should be taken with a grain of salt because there are so many different site characteristics, e. g., a big tree which can suck up all of the water or a south facing exposure vs. a north or east facing.

In my experience, Minutifolia doesn't really "like" extremely hot summer temps. When I grew it in Newhall, it flourished with shade from taller plants during the worst of the summer. As long as it remained irrigated (all watering there was over head via hose and oscillating sprinklers), it continued flowering, as did Stellata. I had it planted in the ground there, well mulched with all the horse manure I could schlep. Here, they remain canned. The happiest are those which receive shade from other roses planted in the ground, with the exposed one complaining the most. I water them regularly and they grow and flower as expected.

An extreme part of the sunburn issue here are the Pacific Flathead Borers. Sunscald is an open invitation to these nasties. By the time you usually discover their presence, they're on their way toward the bud union or crown of the plant. Once there, forget saving the plant as they are most often toast. Good cultivation, proper watering and avoiding injuries are the suggested prevention.

But, listen -- we tried a series of four different roses here, against a low, south-facing retaining wall. The last thing we planted there was the China, 'Louis Phillipe.'

And, Ta-DAH! 'Louis Phillipe' LOVED that spot, and grows like crazy. It slows down on bloom through the summer, but does not defoliate, and doesn't go completely out of bloom.

NOTE: It IS irrigated ... But so were all the ones that died, and it wasn't enough water for them.

So, I would say -- look at Chinas, as well as Teas.

Jeri

Yes Jeri I know I need to look at Chinas!! Workhorses, but often hard work is what you need.