Drought-tolerant perennials a good choice for your garden

Drought-tolerant plants

Photo: Contributed

Happy gardeners took away thousands of drought-tolerant perennials last year at the Okanagan Xeriscape Association?s fall plant sale, which will be held Sept. 23, 10 a.m. to 2 p.m. this year at the Xeriscape Demonstration Garden on Gordon Drive in Kelowna.

It’s almost sale time.

Mark your calendar for the non-profit Okanagan Xeriscape Association’s second annual fall plant sale Sept. 23 from 10 a.m. to 2 p.m. in our xeriscape demonstration garden in front of the H2O Aquatic Centre at 4075 Gordon Drive in Kelowna.

Fall is the best time of year to plant perennials, giving them an opportunity to begin to get established before the hot and dry conditions of summer. This sale is a fantastic opportunity to purchase a wide selection of xeric plants from OXA and Wild Bloom and Xen Nurseries.

Additionally, master gardeners will be on hand to answer all of your garden-related questions.

With the unprecedented drought province-wide this year there is no better time to transition to xeriscape beds in your own garden. In previous columns I have discussed the interesting physiological adaptations plants have taken on to survive drought and while these adaptations are fascinating, so too is the stunning sustainable aesthetic which is xeriscape.

At our sale we will offer plants encompassing a diverse colour palette from hot reds and yellow shades to cool blues, purples and greens.

One of the plants I am excited to offer this year is Ceratostigma plumbaginoides, known commonly as leadwort or plumbago.

Native to Western China, Ceratostigma plumbaginoides spreads by rhizomes to form an attractive groundcover featuring late-season, Gentian-blue flowers held above shiny green foliage.

As the fall temperatures drop, the foliage of leadwort transitions to a bronzy-red which is in stunning contrast to the deep blue blooms.

Also putting on a spectacular fall display are the various Agastaches. We will have three cultivars available for purchase: Little Adder, Coronado Red, and Double Bubble Mint. Agastache makes a great addition to the late season garden and all are favoured by a wide-variety of pollinators, but seldom bothered by deer.

Little Adder, featuring blue-purple blooms, has been propagated from our West Kelowna xeriscape demonstration garden where it continues to thrive even without irrigation in the face of stage 3 watering restrictions enacted Aug. 23 to protect the available water supply needed to fight the MacDougall Creek Wildfire.

Coronado Red and Double Bubble Mint feature warm shades of orange and magenta respectively.

These compact, long-flowering hybrids bloom earlier and longer than the traditional species of Agastache, with showy flowers sure to attract hummingbirds to your outdoor space.

For those of you looking for pure sunshine yellow, look no further than the new perennial Gazania. That’s right, long considered an annual in Northern gardens, the new Colorado Gold Gazania linearis is perennial in zones 4a-8, and so reliably hardy in the Okanagan Valley. This Gazania linearis features daisy-like, golden yellow flowers which begin blooming in the spring and continue throughout the growing season.

No fall garden would be considered complete without including a sedum or two and we will have both tall and prostrate varieties including Angelina, Blue Spruce, Dark Magic, and Dazzleberry. Dazzleberry is a new cultivar from the Sunsparkler series which features smokey-blue foliage absolutely covered in raspberry blooms.

These tough beauties are not particular about soil quality and extend the bloom period late into the fall, many looking fantastic with a covering of snow on their umbral flowers.

All of the above-mentioned plants will benefit from being planted this fall when the ambient air temperature has begun to cool, yet the soil is still warm to encourage good root establishment prior to going into dormancy for the winter.

There is still time to head to makewaterwork.ca and take the pledge to conserve water and in doing so become eligible to win one of two $500 gift certificates.

The Okanagan Xeriscape Association is extremely grateful for the ongoing financial support of the Okanagan Basin Water Board and is proud to be collaborating with them on their Make Water Work campaign.

Sigrie Kendrick is a master gardener and executive-director of the non-profit Okanagan Xeriscape Association and can be reached at 778-363-8360 or by email at [email protected].

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.

It's time to set water priorities in your garden

Water use in a drought

Photo: Judie Steeves

Despite the hot, dry summer, this vibrant and colourful collection of plants growing in the OXA xeriscape demonstration garden in Kelowna is still thriving on very little water, partly due to the generous application of a healthy mulch early in summer.

As we watch our favourite plants wilt and dry up under increasing water restrictions, record-setting drought conditions and extreme heat, decisions need to be made about where to draw the line.

In most water districts, hand-watering is still permitted, but that should be limited to the most efficacious instances, in order to conserve water for domestic consumption, firefighting and agriculture.

Most lawn grasses, without regular watering, will dry up and go brown. However, they will return to their usual lush green state once water is returned to the roots. So, they are not a priority for watering at this stage.

In fact, to have a green lawn today is considered by many to be a reason for shame, because it means you’re not doing your part to conserve water in a serious drought.

Many perennials, including the Gloriosa Daisy, do not react well to severe water restrictions, but if you cut them back to the ground, they’ll likely return to their normal beauty next year. There’s another low priority for water and a reason to do some ground-level dead-heading.

In fact many plants that look dead above the soil line will regrow from their roots once they again receive water. One of the plants in our Okanagan Xeriscape Association demonstration garden that regularly does this is the Monarda didyma, known commonly as Beebalm.

One of the best practices to conserve water in your garden is by applying an organic mulch before your herbaceous perennials leaf out in the spring.

Both Glengrow and Nature’s Gold are excellent choices and will limit water loss from the soil surface through evaporation, decrease the soil temperature during hot weather and limit weed growth so your plants are not competing for available water with weeds.

Such organic mulches also feed your plants, leading to healthier, more-resilient plant material.

The manner in which you water and the time you do so can be instrumental in conserving water. Obviously all types of sprinklers are extremely wasteful as they lose so much water to evaporation.

Drip irrigation is the very best choice and is the most-effective irrigation as it directs the water where it is needed at soil level and to the root zone.

The Regional District of Central Okanagan has determined you can decrease your water consumption 30% to 50% just by switching to drip irrigation.

Definitely do not water in the heat of the day as this leads to yet more water lost to evaporation. Instead set your irrigation to go on between dusk and dawn when the temperature is lower.

Consider the water needs of your plants and group them accordingly. I can’t tell you how many times I have seen high-water-need plants, such as hydrangeas grouped with low-water-need plants such as ornamental grasses.

In this situation the lower-water-need plant will drown, often to the detriment of plant health.

Consult our plant database at www.okanaganxeriscape.org for information about the water requirements of hundreds of plants which we have broken down into three categories, indicated by either one, two, or three water drops. One-drop plants will require an average of 0 to three inches of supplemental irrigation, plants in the two-drop category will require four to seven inches of supplemental irrigation and thirsty three-drop plants require eight to 11 inches.

These calculations have been made based on mulched, average, well-drained soil with good organic content. If you have heavy, slow-draining clay soil, you may require less irrigation, while sandy, fast-draining soil requires more irrigation.

The bottom line is turf grass is definitely not where anyone should be using our precious water resource.

Visit the www.makewaterwork.ca website and take the pledge to use water more efficiently on your landscape and become eligible to win one of two $500 gift certificates.

The OXA UnH2O xeriscape demonstration garden at 4075 Gordon Drive is looking spectacular right now, so stop in and see first-hand the beauty, resilience, and sustainability that is xeriscape.

Don’t forget to mark your calendar for OXA’s second annual fall plant sale, Sept. 23 between 10 a.m. and 2 p.m. in the demonstration garden.

The Okanagan Xeriscape Association is extremely grateful for the ongoing financial support of the Okanagan Basin Water Board and is proud to be collaborating with them on their Make Water Work campaign.

Sigrie Kendrick is a master gardener and executive-director of the Okanagan Xeriscape Association and can be reached at 778-363-8360 or by email at [email protected].

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.

Plants need strategies to deal with the heat too

Hot weather and plants

Photo: Judie Steves

Pineleaf Penstemon or Penstemon pinifolius has adapted to drought by having narrow leaves which reduce the surface area for water loss. This is just one strategy used by xeriscape plants to survive drought.

Adaptability and climate-resilience are essential to survival for plants that are native to the Okanagan Valley’s arid climate, with its hot summers and low rainfall.

But escape from death under a blazing summer sun can be achieved in a variety of ways.

Biologist Josh Smith is general manager of XEN Nursery in West Kelowna, which grows and propagates native and xeriscape plants for use through the Okanagan on ecological restoration projects. He is also a member of the board of the Okanagan Xeriscape Association.

He explains drought resistance can be achieved in a number of ways, including escaping drought; avoiding drought and tolerating drought. A common tactic xeriscape plants employ is to cleverly skip the dry summer months entirely, by blooming during the moist spring months and quickly setting seed for the next generation, before dying back until the next fall or next spring.

Good examples of this strategy in the Okanagan native plant world are the City of Kelowna’s official flower, the Arrow-leaved Balsamroot or Balsamorhiza sagittata.

These cheerful yellow sunflowers bloom in masses on the hillsides in early spring, then the big arrow-shaped leaves curl and dry up during the hot summer. However, the plant lives on underground, storing moisture in its deep tap root, ready to sprout new green leaves with winter snowmelt, longer days and in the spring rain and sunshine.

Spring bulbs fit in this category as well, shooting up in the spring from the nourishment stored from the previous year in their bulbs or corms; blooming lustily for a few days or weeks, then slowly dying back to ground level as the weather warms up.

During their short lives above ground they bloom, set seed, store nourishment underground, and disperse seeds to ensure a new population is created.

Smith says the second adaptability trick plants use is to avoid drought by maintaining a high water content, either by minimizing water loss or by maximizing water uptake.

One method is to reduce the amount of sunlight that can enter the leaves, which decreases light reactions and associated water use.

Such plants include those with silvery or dusty foliage such as the native Rabbitbrush or Ericameria nauseosa, or the Pearly Everlasting or Anaphalis margaritacea.

In the garden, a great ornamental example is Silvermound or Artemisia schmidtiana.

Drought avoidance is illustrated also by plants with deep tap roots which are thus not susceptible to surface drying of the soil. Native plants which are good examples are the Arrow-leaved Balsamroot, which is also a Drought Escape Artist, Yarrow or Achillea millefolium and Brown-eyed Susan or Gaillardia aristata.

In our gardens, good examples are domestic cousins of the native gaillardia and yarrow family plants, as well as such plants as the Missouri Evening Primrose or Oenothera macrocarpa.

Succulents fit into the drought avoidance category as well, storing water in their fleshy leaves or stems and reducing the surface area to minimize water loss and keep cool.

Cactus fit into this category, as well as agaves, Hen and Chicks or Sempervivum and a huge family of plants that are both native and are propagated for garden use: the sedum or stonecrop family. This includes low-growing Sedum divergens and two-foot tall Sedum Autumn Joy or Autumn Fire, as well as the native Sedum lanceolatum.

Lastly, Smith says drought tolerance is a tactic used in either morphological (shape and form) or physiological (how they interact with the environment), or biochemical ways (changes to their internal body chemistry and pathways).

Many plants have more than one adaption.

A great expression of a morphological adaptation that xeric plants use is to have narrow leaves which reduce the surface area for water loss. A good garden example is the Pineleaf Penstemon or Penstemon pinifolius and another is Russian Sage or Perovskia atriplicifolia (which also has a long, deep tap root to search for water).

When selecting plants for your garden, keep in mind these various strategies plants use to survive heat and associated drought conditions and look for plants that use these strategies so they will survive in your landscape.

Coming up

Such xeriscape perennial plants will be offered for sale to the public at the OXA fall plant aale set for Sept. 23, from 10 a.m. to 2 p.m. in the OXA demonstration garden, the UnH2O Garden, in front of the H2O Aquatic Centre in Kelowna.

I will feature some of the plants that will be available for purchase in upcoming columns.

Especially with our current drought situation, be sure to visit the www.makewaterwork.ca website and take the pledge to use water more efficiently on your landscape, and become eligible to win one of two $500 gift certificates.

The UnH2O demonstration garden at 4075 Gordon Drive is looking spectacular right now, so stop in and see first-hand the beauty, resilience, and sustainability that is xeriscape.

The Okanagan Xeriscape Association is grateful for the ongoing financial support of the Okanagan Basin Water Board and is proud to be collaborating with them on their Make Water Work campaign.

Sigrie Kendrick is a master gardener and the executive-director of the Okanagan Xeriscape Association. She can be reached at 778-363-8360 or by email at [email protected].

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.

Why it's nuts to litter your landscape with fabric

Landscape fabric not best

Photo: Judie Steeves

Feed your plants while you smother weeds by using an organic mulch as Sigrie Kendrick (right) and an OXA volunteer do here at the West Kelowna Xeriscape Spirit Square Garden. Landscape fabric just ends up topped with weeds or littering the landscape.

It’s insanity.

Albert Einstein is generally believed to have been the one to state that the definition of insanity is doing the same thing over and over again and expecting different results.

This concept could certainly be applied to the continued use of geotextiles, also known as landscape fabric, by the landscape industry.

I was pondering this recently while working in the extreme heat in an area behind the Okanagan Xeriscape Association’s demonstration garden that has landscape fabric covered with rocks, that is completely covered in weeds.

The sweat was running in my eyes so much that I couldn’t see, and I was grumpy—a rarity for me at work in the garden. Why was I doing this? Well, the simple answer was if I didn’t weed that area adjacent to the garden, all the weeds would migrate into the garden.

But it got me pondering the ridiculous notion that landscape fabric works in permanent landscapes, when our experience as an industry makes us well aware it does not.

Landscape fabric is useful in reducing weeds in seasonal vegetable gardens and other areas of production, but the crossover to permanent landscape areas has been an utter failure.

Landscape fabric deteriorates quickly if subjected to sunlight, and any organic matter on the fabric will soon be colonized by weeds growing through the fabric. Any attempt to eradicate these weeds leads to tearing of the fabric, which is then further compromises it as a barrier, leading to more weeds.

From an aesthetic standpoint the fabric is now at its worst, ripped and flapping in the breeze—not effective and definitely not attractive. So, stop using landscape fabric to control weeds. It doesn’t work. The fabric quickly becomes a challenge to plant health, aesthetics, and weed control.

The reality is, weeding is an integral part of gardening that we should embrace, rather than complicate by installing landscape fabric.

An organic mulch is far more effective for both weed suppression and plant health. Such mulches can be reapplied throughout the life of your landscape, feeding the soil and plants and acting as a very efficient barrier against weeds.

Coming up

I know many of us are boating, camping etc. right now but save the day on your calendar for OXA’s fall plant sale, to be held Sept. 23, from 10 a.m. to 2 p.m., in the OXA demonstration garden—the UnH2O Garden—in front of the H2O Aquatic Centre.

I will be featuring some of the plants that will be available for purchase in upcoming columns.

With our current drought situation, be sure to visit the www.makewaterwork.ca website and take the pledge to use water more efficiently on your landscape, thereby becoming eligible to win one of two $500 gift certificates?

The UnH2O demonstration garden at 4075 Gordon Drive is looking spectacular right now, so stop in and see first-hand the beauty, resilience, and sustainability that is xeriscape.

The Okanagan Xeriscape Association is grateful for the ongoing financial support of the Okanagan Basin Water Board and is proud to be collaborating with them on their Make Water Work campaign.

Sigrie Kendrick is a master gardener and executive director of the non-profit Okanagan Xeriscape Association and can be reached at 778-363-8360 or by email at [email protected].

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.