Friday, May 23, 2014

My favorite plant this week: Hebe 'Wiri Blush'

My favorite plant this week is another one that came through our recent heatwaves unscathed, Hebe 'Wiri Blush.'  This is not classified as a drought tolerant plant but it is considered heat tolerant.  Specifically, it's suited to AHS heat zones 7-12, which means it can tolerate conditions in which it's exposed to heat of 86F (30C) or greater for more than 210 days per year.*  When our temperature exceeded 104F (40C) last week, the plant didn't wilt, the flowers didn't shrivel, and the leaves didn't burn or drop.  The plant looked as good this week as it did at the end of April - better, perhaps, in that the heat seems to have prompted blooms that are normally associated with summer.

Hebe 'Wiri Blush' sits in my backyard border in front of one Phormium 'Dark Delight' and alongside 2 others



This is another plant I bought principally for its foliage.  The narrow leaves are a glossy green, edged in magenta.  The undersides of new leaves and the plant's stems have the same magenta color.  The plant is evergreen and grows 3-4 feet (90-120 cm) tall by 4 feet (120 cm) wide.  It seems to be a relatively fast grower - mine, planted in January 2013 from a 1 gallon pot, has already reached its mature size.  Its compact form is easily maintained with a little light pruning.

This foliage close-up shows the magenta undersides of the stems and the new growth



It grows in full to partial sun and normally blooms in summer through fall.  The flowers are a bright pink color.  They're also attractive to bees.

The flower spikes are about 3 inches long and hold up surprisingly well in cut flower arrangements



This New Zealand native requires good drainage and regular water.  Dry summer heat is said to shorten its life span.  As that's what it receives in my garden, we'll have to see how it does in the long haul but I'm very pleased with it thus far.  So pleased in fact, that I recently picked up another one for placement in my "red bed."  For those of you in cooler climates, this Hebe is said to handle low temperatures in the range of 0 to 10F (-18 to 12C).




Hebe 'Wiri Blush' is my contribution this week to the favorite plants meme hosted by Loree at danger garden.  Click here to see Loree's favorite of the week and to find links to other gardeners' selections.

*On a separate but related topic, looking at the heat tolerance of this plant led me to a closer examination of the American Horticultural Society's Heat Zone Map.  Unlike the USDA cold hardiness zones, I wasn't able to find a tool that linked heat zone directly to postal zip code.  I was left to deduce my zone based on my own possibly questionable reading of the AHS color-coded state map.  My reading of the 1997 map suggests that I reside in heat zone 6 or below, although average temperature data for downtown Los Angeles, which normally tracks our local temperature fairly closely, suggests that a zone 7 classification may be more accurate.  However, I have to wonder whether either estimate reflects the warming trend.  I'm also unsure whether this heat index helps me in assessing a plant's resilience in handling abrupt temperature fluctuations, such as those we've been experiencing.  Have you made use of the AHS heat tolerance index?  Do you find it of value in making plant selections?

10 comments:

  1. Yes--heat tolerance vs drought tolerance vs cold tolerance. Your post reminded me that they are NOT THE SAME. Around here, we have to consider cold tolerant vs. wet tolerant. Maybe, heat tolerant, too. For us, I think wet (or combo of wet AND cold) kills a lot more plants than does cold alone.

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    1. Yes, I think you're right that the issues are mainly due to a combination of factors. Here, the biggest issues are summer heat, wind and drought. Even when you provide lots of water, it's hard to counteract the impact of the dry air.

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    2. Hi Kris, wanted to see how this plant is doing two years later. I just purchased 6 of them. Trying to figure out where to plant them.

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    3. Mine is doing fine in my sunny backyard border. It's flowering heavily at the moment. I tip prune periodically to refresh the plant. Of all the Hebes I have, this remains my favorite.

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  2. I hope it does well for you--being so close to the ocean you have a good chance of keeping it happy. Here they loose the bottom foliage and look bedraggled by the second or third year.

    I think the USDA/AHS stuff--with a Mediterranean climate (or South Florida) all bets are off. Just too different.

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    1. The Sunset zones may provide the best guidance as they at least take multiple factors into consideration. Unfortunately, plant growers (even the local ones) rarely provide ratings based on that information.

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  3. 104?? That's insane! I'm glad the hebe survived your heat wave. I love hebe but after we hit -2 this winter, I'm done bothering with marginals. I lost 2 shrubs and numerous plants. But hopefully yours will prove to be keepers since they've done so well. The flowers remind me of veronica. :o)

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    1. In researching this post, I discovered that Hebes were once classified as Veronicas so your instincts are right on target, Tammy.

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  4. Oh that's a beautiful hebe! I've found in our climate the smaller leaf ones are happy, anything as large as these tends to not live through a slightly colder than average winter. Ah well, I can enjoy yours!

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    1. I now consider anything that beats the heat (and, ideally, tolerates drought too) beautiful, Loree.

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