by Judy Kautz, OSU Extension Master Gardener
In the past few weeks, we have been made aware that we are once again experiencing a dry period in certain parts of our beautiful state. It doesn’t matter where you live or if your garden is in sun or shade — you’ll have to water perennial plants sometimes. Here are a few things to keep in mind so you can give your perennials the water they need to thrive and look great.
In general, perennials need about an inch of water per week to be healthy. That can come from rain or irrigation or a combination of both. Use your rain gauge to determine how much rain has fallen and then subtract that amount from an inch. This will tell you how much you need to supplement each week. In general, many established perennials can get by with less than this, and newly planted ones may need a bit more, especially in hot weather.
How often should you water perennials? A quick drink every day just encourages spindly roots. Instead, deep and less frequent watering is best to promote long roots. They’ll grow down into the ground so they stay cooler and absorb moisture and nutrients that are held there. Perennials with an established root system can handle a little drought stress, too.
Watering deeply and less frequently helps promote long roots.
When should you water perennials? Early morning is the ideal time of day to water your garden. This allows you to soak the roots and lose little water to evaporation. Also, foliage dries quickly as the sun and temperatures rise, so plants are less prone to fungal diseases that settle in on wet leaves. Watering in the middle of the day is less ideal, especially with sprinklers, because the small droplets often just evaporate in the air and never reach the soil. Also, winds are stronger at that time and can lead to uneven water distribution and waste as it ends up on your sidewalk instead of your plants. If your schedule doesn’t allow you to water in the morning, then late afternoon to early evening is another option. Do it before 6 p.m., though, so leaves have adequate time to dry before nightfall — this will reduce the chance of disease.
Here are some signs you need to water perennials: Noticing wilted plants is usually a good indicator that it’s time to water. However, droopy leaves and stems aren’t necessarily a signal that the plant is drought-stressed. Many perennials wilt in the afternoon, especially on hot, sunny days, but then they’re fine by morning.
The best way to know if your plants need a drink is to check the soil moisture. Use a trowel to dig down about 3 to 4 in., where the roots are, to see if it’s moist or dry. Some perennials, such as ligularia (Ligularia spp. and hybrids), give an obvious sign that they need a drink, by overtly drooping. If this plant wilts and still looks that way in the morning, you’ll know it’s time to water.
Some watering techniques include hand watering, which can be a relaxing chore, especially on a warm summer day. Be sure to aim your hose-end close to the ground, near the base of the plant. This puts water at the roots where it’s needed. It’s a good method for giving extra moisture to newly planted perennials and ones with high water needs, such as astilbe (Astilbe spp. and hybrids).
Be sure to aim your hose-end close to the ground, near the base of the plant.
Oscillating and impact sprinklers work well for lawns and large perennial borders. They save you time and are easy to set up, but water loss through evaporation is common and flowers can flop with the weight of too much moisture. Here’s a tip: Set out a rain gauge when you use an overhead sprinkler and watch the time to see how long it takes to fill up to ½ in. Use the minutes to figure out how long to keep the sprinkler going, based on how much water you need to supplement. A timer can help you give just the right amount, without wasting. It can shut off automatically so you don’t have to worry about water running on and on.
Soaker hoses and drip irrigation systems supply water closer to the root zone, and you can leave them in place all season and just hook up a hose when it’s time to water. Cover up soaker hoses with a little mulch so they’re not as visible during the growing season, then drain and put them away for winter storage. Whatever methods and tools you use for watering, keep an eye out for leaks. Repair hoses and replace washers to make sure the water is going where you need it.
Soaker hoses like this are a super efficient way (and easy) way to water a perennial garden.
by Courtney DeKalb-Myers, OSU Extension Horticulture Educator
August is here. July came with the sun and Norman hasn’t seen a decent rain since. The water bill is creeping upward and dragging the hose around to water does not sound fun. The gardens are about as worn out as the gardeners. One way to avoid this situation is to use drought tolerant plants within the landscape. Drought tolerant plants are more adapted to these water-stressed conditions and will thrive through the heat of the summer. Consider using some of these plants to make this time of year less stressful.
Stonecrop blooms with clusters of pink flowers in the fall. It has succulent like foliage and prefers a full sun location. Consider the popular cultivar 'Autumn Joy'.
The best drought tolerant fern, Japanese painted fern adds a beautiful silver foliage to the gardens. It is low to the ground and makes a great border in shade gardens.
Sometimes referred to as whirling butterfly, guara has a dance-in-the-wind appearance. Flowers come in pink or white and a bronze foliage variety is available.
A classic in any prairie bed, coneflowers are highly adapted to drought conditions. More cultivars are available on the market, including different colors and dwarf varieties.
Autumn sage is a bright pink perennial that will bloom all summer long. It is medium sized with and upright form. The reddish pink, tubular shaped flowers are a great attractant for pollinators.
Russian sage has grey-green foliage with wispy purple flowers. It performs best in full sun. It can grow quite tall and may be useful as a backdrop in the garden.
by Judy Kautz, OSU Extension Master Gardener
Have you had trouble keeping your plants alive throughout the summer growing season? Gardening in Oklahoma can be challenging in the summer months, for sure; bugs, heat, low rain, etc. all are factors that can severely affect your plants. Here are ten low maintenance plants you cannot kill! All of them are suited to our frost zone 7. Although the season is winding down now, plan ahead for next year!
Marigolds are one of the hardiest flowers that you can plant in your garden, which is why they are seen at nearly every home in the country. In fact, they are well known by gardeners to be a drought tolerant plant that can handle a lot of heat. Marigolds are annual flowers, so when the first frost hits, their growing period ends.
If you are looking for a plant to brighten your garden, the daylily is a great option that comes in a plethora of colors. These blooms will only last for a day, but they will continue to appear throughout the summer in our zone. These plants grow best in full sun, and they are able to tolerate drought conditions, which means that even if you forget to water these plants, they will continue to do well.
One of the most low-maintenance plants that you can consider for your garden is cosmos. These hardy plants are so easy to grow that they can seed themselves and grow with very little care in the warmer areas of the country. They do best in full sun, but they will also grow in partial shade, which means they can be planted anywhere in your garden.
Cosmos are hardy plants that reseed themselves and require very little care.
Begonias are colorful flowers that grow well in Oklahoma, but remember they are sensitive to frost, so will not last past our first cold snap. This is a plant that loves the shade, so if you do not have a sunny garden, this plant will thrive here. It can also tolerate drought conditions and a lot of sun, so regardless of where you plant it, the begonias will grow. This is a great option for a garden that does not get a lot of sun.
Hostas are very adaptable plants that grow in shade to part shade, and this is a plant that does not mind cooler temperatures. When the weather is below 40 degrees Fahrenheit, this plant will go dormant through the winter and reappear again in the spring. They tend to do well in partial sun, especially the golden varieties with foliage that turns yellow in direct sunlight.
Goldenrod is a plant that is mostly known in its wildflower form, but it will also make a great addition to any garden because it will basically grow on its own. Their tiny yellow blooms add brightness to your garden, and they will attract butterflies and bees as well. These plants can handle full or partial sun, and they are drought-tolerant, deer-resistant plants that can easily grow to be eight feet in height.
The tiny yellow blooms of goldenrod add brightness to your garden, and they will attract butterflies and bees as well.
Are you looking for a bright pink, purple, or crimson flower to attract butterflies, bees, and birds to your garden? The coneflower grows up to five feet in height, which is perfect for adding depth to your garden. These plants grow well in Oklahoma; they prefer full sun, but they can grow in shady conditions as well. Their blooming period begins in early summer and continues until or through the first frost of the year.
If you are looking for a lot of ground cover in your garden, yarrow is a plant that spreads quite rapidly. Growing up to four feet tall, yarrow can handle a lot of heat, and it is also drought-resistant, so if you forget to water it, it will still survive. Yarrow comes in yellow, white, pink, and red blooms, and will continue throughout the entire summer, especially if you deadhead the plant.
Zinnias are very adaptable plants that can grow to be up to three feet in height. They prefer full sun, though they will grow in the shade as well. These are drought tolerant plants that will attract butterflies to your garden. The blooms from this plant last all summer, and they can be red, pink, orange, purple, yellow, and white in color.
Zinnias are very adaptable plants that can grow to be up to three feet in height and come in a huge variety of colors!
Finally, if you have a garden full of poor soil, then coreopsis is a great plant to consider. It can thrive in dry, hot, and humid conditions without a lot of care from you. This plant is often seen as a wildflower, but they can add some lovely orange, yellow, and red blooms to your garden environment. They will also attract bees, butterflies, and other pollinators to your garden.
There are several other plants that will thrive in Oklahoma during the summer, all available at local nurseries. Try some of these beauties for colorful plants that will last all summer!
by Judy Kautz, OSU Extension Master Gardener
Are your hibiscus blooming? They are beginning to show their glorious color in our neighborhoods? Everyone loves the large, flamboyant blooms of the hibiscus plant, which add bright color to any yard. There are two types of hibiscus that we enjoy in Oklahoma: tropical hibiscus and hardy hibiscus, and both grow well in Oklahoma as shrubs or potted plants in a sunny spot in your garden.
Often referred to as rose mallow, the hardy hibiscus is unlike any other flower in the garden, offering blooms that are both delicate and huge. Flowers range from 3 - 4 inches across to a gigantic 12 inches in diameter. Hardy hibiscus plants are grown as woody shrubs and can grow up to five feet tall and three feet wide. They are hardy down to -30 degrees F, and prefer full sun and fertile, well-drained soil. The foliage of the plant is very attractive, with heart-shaped leaves. Most hibiscus shrubs tend to leaf out late in the spring, and they will hold their green colored leaves late into the fall.
Hardy hibiscus come in a variety of colors, varying from red, white, lavender, purple, pink, and magenta. They leaf out very late in spring, so don't think they're dead and chop them down. Be patient, and in a few weeks you'll have attractive foliage (often finely cut, and sometimes copper colored) and soon a summer full of spectacular blooms. They begin blooming in mid-summer and will often continue to produce flowers until fall. Many hardy hibiscus blooms grow to the size of dinner plates! They definitely add stunning drama and color to any landscape.
Hardy hibiscus blooms comes in many stunning colors.
There are several plants that are beautiful companions to hardy hibiscus in your garden. Tickseed, or coreopsis, are slightly smaller than hibiscus and bloom in yellow shades which are very complimentary. Try a mixture of other easy-to-grow companion plants, such as Shasta daisies, daylilies, delphinium, allium, poppies, peonies and bearded iris. They all grow well in the same soil conditions, light and water requirements as the hardy hibiscus. For a great example of the combination of hibiscus and Shasta daisies, visit the Cleveland County Master Gardeners Demonstration Gardens, located west of the gravel parking lot at the Cleveland County Fairgrounds. These beauties are in Bed 2, Easy Perennials.
The hardy hibiscus bloom is stunning when planted with Shasta daisies, and blooms can reach the size of dinner plates.
Tropical hibiscus should be grown in a container or planter in our area, as they will not survive our cold winters. They will winter over in your garage or house, so long as they are protected from freezing temperatures. Their foliage resembles the hydrangea, with long graceful leaves; they also come in a variety of colors, ranging from white, red, yellow, pink, and orange. They, too, prefer full sun, but can tolerate some shade, as long as they get at least 6 hours of sun a day.
Tropical hibiscus blooms are generally smaller than hardy hibiscus, and often come with double petals like “Apricot Brandy” pictured here.
Maintenance of hibiscus is not complicated. Pruning plants is a common way to keep your plants compact, but it isn’t necessary. Do not fertilize your hardy hibiscus after June, as flower production may suffer from the excess nitrogen in the fertilizer; however, tropical hibiscus should be fertilized frequently, since their pots do not retain nutrients. For hardy hibiscus, winter mulching is not necessary, and they are not usually bothered by pests. However, tropical hibiscus are susceptible to a variety of insect pests including aphids, scale, mealybugs, thrips and mites, but most plants are resilient enough to withstand pests and continue to thrive and grow. Also, there are many products such as insecticidal soap available in your local garden center to treat these pests.
Hibiscus plants are a magnet for hummingbirds and butterflies, and provide a vital source of nectar for these creatures. Bees also love the hibiscus, and attracting bees to your yard will help to pollinate your other plants. Add hibiscus to your yard this year for a colorful and beneficial addition to your garden.
by Judy Kautz, OSU Extension Master Gardener
Hellebores are some of the first flowers to pop-up in spring. Not only is this perennial easy to grow but they come in a surprising array of new colors!
There’s a lot happening in the world of hellebores. Recent breeding has introduced new colors, never-before-seen shapes and even longer bloom times for these nearly perfect perennials. Perhaps all this renewed interest in hellebores is because they’re so easy to grow. Perhaps it’s because they bloom way before anything else — allowing you fresh-picked bouquets even in winter. Or perhaps it’s simply because gardeners find their jewel tones so gosh-darn hard to resist. “Their allure certainly arises from their precocious bloom time,” says C. Colston Burrell, author of Hellebores: A Comprehensive Guide. “Gardeners yearn for year-round bloom, and hellebores deliver a dose of spring in the winter months. The flowers are colorful and borne in profusion. They are also long-lasting. Because the showy parts of the flowers are sepals, not petals, they do not fade and shrivel like petals would. The color may persist for several months, carrying the bloom period well into spring.”
Hellebores is often called the rose of winter. The most commonly grown type of hellebore is the diverse group of part shade-loving hybrids known as the Lenten or winter rose. Breeding has produced a wide range of intriguing hellebores. The flowers tend to nod downward (to protect the pollen) and are up to 3 inches across, typically in shades of white, rose, green or purple. Newer hellebore hybrids now have spotted flowers and pointed petals; others are double-flowered or bicolors or even streaked. New leaves emerge at bloom time, and plants grow into an excellent glossy evergreen ground cover.
'Mother of the Bride' hellebore (Helleborus x hybridus) is a perennial with a double apricot flowers with a light pink picotee edge. It needs part to full shade, and grows 18 to 24 in tall and wide. It is cold hardy in USDA zones 4 to 9.
In the landscape Hellebores provide contrast in almost any companion planting. That’s because they set the stage for later-blooming tulips and daffodils, but the hellebore’s sturdy foliage remains to camouflage the dying foliage of the spring-blooming bulbs. Try planting hellebores on a slope, hillside, or in a raised bed where their blossoms are better appreciated. “Since hellebores generally nod,” Colston explains, “planting them on a slope allows you to see the inside of the flowers, which are more alluring in color and pattern than the backs of the flowers. The reason the flowers nod is to protect the reproductive structures — stamens and pistils — from frost damage.” Throughout most of North America, hellebores wait until the worst of winter is over to begin blooming around February and March, when the snow has melted or is just beginning to melt. All the more reason you should want to have plenty of hellebores on hand to properly herald spring’s long-awaited arrival.
Garden Gate offers some tips for growing hellebores: If you want to divide your hellebores or need to transplant, do so in the fall. Dig up the whole plant, wash off the soil, then divide with a sharp knife between growth buds. Leave at least three of these dormant little shoots on each of the divisions. Hellebores frequently seed in large numbers around a parent plant, which can be dug up and transplanted. However, these hybrids will not be the same as the parent in color and form.
'Golden Sunrise' hellebore (Helleborus x hybridus) is a perennial with single pale-to deep golden-yellow flowers with contrasting red starburst centers. It needs part to full shade, and grows 18 to 22 in tall, 20 to 24 in wide. It is cold hardy in USDA zones 4 to 8.
Hellebores appreciate plenty of sunlight during the winter when they are beginning their growing season, so site your plants in dappled shade or beneath trees that drop their leaves in autumn. Also, be careful not to plant hellebores too deeply. This can hinder flower production, so make sure the crown of the plant is just below the soil surface.
All parts of the hellebore plant are toxic. That means deer and rabbit typically do not bother them. People who are sensitive to the alkaloids in the leaves should wear garden gloves to avoid developing a mild skin irritation after handling.
Find a new hellebore for your garden. American breeders started bringing home garden-worthy hellebores in the 1980s. Today’s spectacular hybrids in shades of purple-black, plum, burgundy, lime-green, shell-pink and white are the result of hybridization of multiple species. Most of the best hybrids available in North America today are seed strains, some developed by making controlled crosses each season, while others come more or less from open-pollinated plants. Check out the gallery below to meet some of the more recent introductions from breeders here in the United States.
'Confetti Cake' hellebore (Helleborus x hybridus) is a perennial that blooms with double white flowers with burgundy speckling concentrated toward the centers. It needs part to full shade and grows 18 to 24 in tall and wide. It is cold hardy in USDA zones 4 to 9.
I hope you will try this beautiful variety of plants in your landscape. They will reward you in early spring with gorgeous blooms that will stay around for several months.
by Judy Kautz, OSU Extension Master Gardener
Spring is here and your local garden center has new perennial plants for you! Choosing plants from rows and rows of the same type of perennial can be daunting, especially when you want to pick the very best one to take home. Which plant do you pick when some have buds, some are blooming, and others only have foliage? Here are some selection tips to make your shopping trip easier.
First, do you choose plants in full bloom? Not really, since they have already bloomed and the blooms may not last much longer. Pick instead the plant that has buds or the beginnings of flower spikes as your best option. A plant like this is best, because you can see just enough of the flower to be sure you are getting the cultivar and the bloom color you want. Remember that plants do get rearranged by customers, so the sign in front of plants may not necessarily reflect what is there! Tags in pots also get moved around, so seeing the beginnings of the bloom will tell you what you are buying.
Next, size definitely does matter. Most often, the largest plant is your best option unless it is leggy. Also, look at the root system to ensure the plant isn’t root bound; a root bound plant (one with a dense mass of roots) can recover, but it will take time. A medium sized plant could root faster with healthier looking foliage after being transplanted, but it might not grow much more this year. Never buy the smallest one if it is the same price as the others, as you will overpay.
Here's an example of a plant that has been root bound in a pot. Avoid these when purchasing perennials unless you are getting a deep discount.
There are some perennials that you should always buy bigger because they are slow-growing; plants like false indigo, Russian sage and peonies fall into this category. Buying the largest plant you can find of these varieties means you will get a bigger impact sooner. With peonies in particular, look into the crown for the plant with most eyes or stems; since peonies are so slow to take off, the more stems, the better. Finally, if you are simply looking for a great deal, choose a plant that is spilling out of its pot, because it can easily be divided into several plants for the price of one.
When purchasing perennials like these peonies, buy larger plants with more stems.
If you see plants that are deeply discounted because of damage, or you see a plant you think you might be able to revive, those can be difficult to pass up. However, carefully examine the plant first before you decide to spend your money. It will not hurt a plant to look at its roots; simply straddle stems with your fingers and gently tip the top.
Here are some things to look for if you are considering buying a damaged or deeply discounted plant. Avoid a plant that has been newly transplanted, with roots that don’t fill the pot. Although it is okay to buy if you get a really good discount, remember that it will be a long time before it takes off in your garden. Second, look for pest damage – lacelike holes in discolored foliage – most likely caused by Japanese beetles. These insects can mark plants for others to find later, so skip insect-damaged plants. If you see shriveled brown or pale leaves, the plant has not gotten enough water or protection from strong sun. If foliage looks really stressed, this plant will rarely bounce back, so leave this one on the shelf. Finally, avoid plants with dead crowns or roots that are easy to pick off; these are signs of overwatering. Since rotted roots never recover, do not buy overwatered plants.
Plants for sale which demonstrate insect damage like this one should not be purchased, even at a discount.
If you follow the tips when you choose your perennials, you should bring home plants that will flourish in your garden. And to see many examples of all kinds of plants, visit the Master Gardener Demonstration Gardens at the Cleveland County Fairgrounds, southwest corner adjacent to the gravel parking lot.
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