Monday, June 25, 2012

Garden Tour!

It is always fun to get photos from Nebraska Statewide Arboretum, Inc. members and curators showing us how their gardens are growing.  A few weeks ago we got some photos from Steve Rothe, a NSA member from Omaha.  Steve is an ecologist by education, and professionaly plans and manages habitat restoriation projects. Steve says '' The primary intent of these gardens is native plants and their ecological value.  But I also want a pretty garden to prove you can have both.  But you can’t just throw natives in a nice bed and expect citified behavior; so the other intent is manageability, control, with open space and mulch.''  The result is a more "gardened" look, mixed in with traditional plants and even a few exotic annuals. Steve says that in these photos are at least 35 native species. We believe you, Steve!

Gardening with natives is not without challenges. Steve tells us that the garden "was was totally overrun by aggressive forbs. This bed had been filled with natives for 8-10 years and became an unmanageable, flopping tangle of big aggressive plants.  Last year I totally revamped it, adding soil amendments, removing most plants, relocating others, and adding some new ones."  He now has a bed dedicated to just the aggressive plants.  Steve warns "
Generally, stick to species from NSA or nurseries; there’s a reason some natives aren’t brought into the garden.  Or, dedicate an island bed to aggressives, and be prepared to weed them out elsewhere."

Improving the soil is important for success.  He gardens in native clay, "I finally bit the bullet and amended substantially with good effect." He tells new gardeners "Amend clay even if you’re a natives gardener with several inches of organic and friable materials."

On maintenance he adds " It is work. Mowing is faster and easier than gardening, but more boring."

Serviceberry (tree in backround)


Coneflower, White False Indigo, Poppy Mallow


Prairie Dropseed, Butterfly Milkweed, Liatris, Eupatorium, Helopsis



Blue Flax, Little Bluestem, Prairie Dropseed and Primrose


Steve's 'Island of Aggressors'

Friday, June 15, 2012

Drought Tolerant Trees and Shrubs

After a very dry stretch of weather, we were blessed with a beautiful rain last evening - a glorious 2" or more over most of the area. I was so excited that I went outside and started to dance - until the lightning and my embarrassed wife scared me back inside. Despite the wonderful rain, we all know that drought is a regular part of the climate story here in Nebraska and the dry weather will return at some point. Thankfully we have a wide-range of landscape plants at our disposal that are well adapted to our climatic extremes.  In fact, many of the prairie plants look their best when the weather and associated soil conditions stress them out a bit (little bluestem is the classic example). Here are a few of my favorite trees and shrubs that do a good job of tolerating drought conditions. Unless otherwise noted, these species are native to the region.

Bur Oaks in Bur Oak Canyon near McCook


Trees
Bur Oak (Quercus macrocarpa): If I could only plant one tree, it would be bur oak. It laughs at our weather extremes. This stand of native trees southwest of McCook attests to their tough nature.

Hackberry (Celtis occidentalis): This species provides yeoman's service to us year after year with very little love or fanfare from we humans.

Chinkapin oak leaves
Chinkapin Oak (Quercus muehlenbergii): is a very beautiful and underutilized shade tree able to tolerate an amazing range of climatic extremes.

Linden (Tilia americana): Only the worst of droughts will slow this tree down.
American Linden
Osage Orange










Osage orange (Maclura pomifera). On a hot, dry day, the shimmering glossy leaves of Osage orange are a welcome site.
Blackjack Oak
Pecan (Carya illinoinensis): Thought not quite as adaptable as its cousin the black walnut, pecan is still one of the best nut trees we can grow.

Blackjack Oak (Quercus marilandica) is a medium-sized, slow growing tree deserving of much greater planting. Its unusual leaves turn a nice red in the fall.

Gambel Oak (Quercus gambelii): This species is meant for the western half of our region where it can survive easily on less than 10" of annual moisture.
Gambel Oak

Boxelder maple (Acer negundo): This tree gets even less love than hackberry, yet will grow in just about any situation.




Shrubs:

Fragrant Sumac
Fragrant Sumac (Rhus aromatica) loves the heat and rewards us with glossy leaves all summer and a nice red fall color.

Rabbitbrush (Chrysothamnus nauseosus): Primarily for western Nebraska, the gray-green foliage of this Xeric plant is unmistakable. Its yellow flowers are butterfly magnets in late summer.

American Hazelnut (Corylus americana) has proven to be very drought tolerant for me in Waverly. Love the apricot fall color.
Sandcherry


Western Sandcherry (Prunus besseyi) is noted for its low, sprawling habit and light green foliage. It most definitely desires well-drained soils. Its cherry fruits are very tasty.

Clove Currant (Ribes odoratum): Though somewhat gangly as it grows, the clove currant is extremely tough and reliable and awards our efforts with very tasty fruits.

American Plum (Prunus americana): Is there anything tougher than the native wild plum?
Snowberry
Snowberry (Symphoricarpos occidentalis): This small, rounded shrub does not get nearly the landscape attention it deserves. It is only mildly suckering, has nice clean foliage and shows off with white fruits in late summer.

Roughleaf Dogwood (Cornus drummondii): This large suckering species is amazingly tough and adaptable and with a nice red fall color and attractive flowers and fruit.
Roughleaf Dogwood

Wednesday, June 13, 2012

A 'How to Water' Primer

Last night the weather man told everyone to "go out and wash their cars. Anything to bring rain."  This is our friendly reminder--it is time to water those new plants! (I am sure as I post this the clouds will start to build.) The untimely rains this year along with heat and wind have been really tough on new plants.

There is no formula for watering. Like any horticultural task there is an art and a science involved.  There are many factors that can influence when, how much, and how to water. Plant type, plant age (newly planted or not), soil type, micro-climate, lawn irrigation, type of watering method to be used etc. Below is not an all-inclusive guide, but hopefully can get you started down the right path. 

Keys to watering properly:
1. Always check to see if your plants need water.  Dig down a few inches and see if the soil is moist.  A long screw driver, a survey stake, or cut off piece of rebar with a point works well. If resistance is felt when inserting the screw drive it is time to water. Plants that were in containers and haven't rooted out yet will need more frequent watering because the soil-less mix can dry out quickly. 
2. Water in the morning or evening to conserve water. That said, watering when you have time is better than not watering at all.
3. Water DEEPLY.  Most people make the mistake of seeing the top of the soil become moist and assuming they have watered enough. In general, a hose (not a sprinkler) running normally for 2 minutes will apply 10 gallons of water.  If you are watering 10 seconds per shrub less than a gallon of water is being put on. If you are hand watering stand at each shrub for a minute or two.  I tend to water everything and then start over and do it all again.  Deep, infrequent waterings are much better for the health and establishment of your plants. 
4. If you are using a sprinkler spend 15 minutes at the start of the season to calibrate it to know how long it will need to run to put on 1" of water. For directions how.
4. You can test how deep you have watered by using a soil probe (long screw driver, or rebar) an hour after watering. Push the probe into the soil. It will go through moist soil easily but become difficult to push once it hits dry soil.
5. Soil types do affect watering.  If you have a very sandy soil you will have to water more frequently. A clay soil you will have to apply more water but less frequently.
5. Trees are best watered by putting a hose on trickle and leaving it there for several hours. Tree gators or five gallon buckets with holes also work as they slowly release water over a period of time.
Tree gator






6. MULCH, but not too much. 2-3 inches of shredded hardwood mulch conserves moisture, slows evaporation, cools the soil and adds organic matter as the mulch decomposes. A hardwood mulch works best. Don't get mulch happy and bury your plants.

Proper Mulch depth
Improper Mulch depth.











7. Don't assume that because it is 'Native' or 'Drought-tolerant' it doesn't need to be watered during establishment (first year or two).  We see this assumption the most with perennials and grasses. Remember that plants are grown in very light-weight potting soil that does not mimic natural soils. This soil drys out very quickly. In nature, native perennials and grass seedlings extend their roots down deeply before putting on much top growth. When we plant them in the landscape it will take a little while for the roots to extend beyond the potting soil and make their way into the native soils. Finding the balance between not watering enough and over-watering can be tricky. Signs of under watering: leaves wilt and curl; older leaves turn yellow or brown; leaves drop; stems and branches die back.


Newly planted plugs of native grasses and perennials
Same landscape, well cared for, two years later.

8. Don't OVER water. Many plants are killed from too much love or ignoring automatic turf irrigation systems. Be especially careful not to over water if these systems are spraying on to trees and landscape irrigation beds. When soil is water logged plant roots are starved of oxygen. Symptoms of over watering look similar to a dry plant. Leaves turn light green or yellow; leaves wilt; young shoots wilt.  
9. Use a rain gauge. If you get 1 inch of rain in a week you won't need to water.  Adjust watering depending on the amount of rain you get.
10. When indicator plants like gooseneck loostrife, heleopsis, monarda and rubdeckia are wilting it is time to water.



Lawn Irrigation Tips:
  • Water deeply and infrequently to encourage deeper-rooting and resiliency
  • Water early in the day to avoid loss from wind and evaporation and limit potential fungal problems
  • Water efficiently (don’t water pavement, make sure any automatic system is working properly, use rain sensor to avoid watering after rain, etc.)
  • Allow summer dormancy of cool season grasses. Fescue cannot go dormant so some watering is required to keep it alive.
  • Lawns should feel firm when you walk across them. If your lawn is squishy you may be over watering.

Friday, June 1, 2012

Prairie Wildflowers

The Beauty of Our Tallgrass Prairie Wildflowers

Nebraska Wildflower Week: June 2nd Through June 11th
http://arboretum.unl.edu/wildflower.html


A Prairie Inspired Garden
          Not long ago eastern Nebraska belonged in the domain of tallgrass prairie. One can only imagine what this land must have looked like to native peoples and early settlers in late summer or fall with grass reaching as high as horseback and stretching as far as the eye could see. Less than one percent of this majestic ecosystem that once stretched from Canada to Texas remains unplowed.  Our prairie soils have become the most productive farmland in the world and are now the lifeblood of our culture and economy. As such, the tallgrass is not coming back.  One thing we can all do to help preserve our natural heritage, however, is to plant and utilize prairie plants in our own yards and gardens. Indeed, our community landscapes have the potential to become vitally important preserves of prairie species. One does not need to convert their entire yard to prairie to make a difference. Just use a few prairie plants as substitutes for some of the non-native species that have become so common in our gardens. For example dwarf false indigo (Baptisia minor) could be planted instead of Russian sage.
      With literally dozens of desirable prairie plants to choose from, it can be difficult to focus on just a few species to highlight in a quick summary like this. Ask me tomorrow and this list will have changed, but for now, the following are some of my favorite prairie flowers deserving to be planted more in the landscape. They should be planted not only for their physical attributes (beauty) but also for the unique stories they tell, the cultural connections they convey and their ability to help support biodiversity.
     

Pale purple coneflower (Echinacea pallida) is known by its slender, hairy leaves and its dramatic shuttle-cock like lavender flowers held high above the plant on slender stalks up to 3’ tall. The flowers are distinguishable by their droopy, widely-spaced ray petals that flutter whimsically in a good mid-summer breeze. Echinacea was a very important medicinal plant to many Native American tribes and was used as a painkiller, as cough medicine and as a tonic for insect bites and other skin abrasions. There may be no better plant to include in the garden for a spiritual connection to past inhabitants of the region.



Dotted Gayfeather

      Dotted gayfeather (Liatris punctata) is named for the numerous tiny dots that speckle its narrow leaves. Sometimes called blazingstar, this wonderful wildflower grows from a stout taproot that can extend up to 15’ deep! This taproot supports unbranched clusters of tight flowering stems resembling lavender bottle brushes and growing from 6” to 30” tall depending on moisture conditions. The flower spikes appear in late summer, just when the garden needs a boost of color. The flowers are a favorite of many pollinators including several butterfly species. Gayfeathers were used medicinally by many native tribes, with the root often used in a tea to treat bladder and abdominal troubles. The root was also a food of last resort for some tribes.
Compass Plant

      Compass plant (Silphium laciniatum) is named for its large basal leaves that often (but not always) align north and south, thus presenting less surface area to the hot midday sun. Compass plant is big and needs plenty of room to grow, so it’s better left to the back of the border and combined with grasses or other plants to help soften its robust presence. The leathery basal leaves of compass plant are deeply lobed and can grow up to 15” long. In mid-summer a hairy flower stalk reaches up to 6’ high and produces several golden sunflowers. The seeds ripen late in the season and are favored by many birds. Compass plant was used medicinally by native tribes for both people and horses. The plant also produces a resinous sap that can be chewed as gum when it hardens.
 Rattlesnake master (Eryngium yuccifolium) is known for its yucca-like leaves and very distinctive green-white flower balls held in clusters atop stems reaching 3-5’ tall. The plant was used by Native Americans to treat rattlesnake bites.

Rattlesnake Master


      Ironweed (Vernonia spp.) doesn’t get much love, primarily because it’s not eaten by cattle or horses and thus can become abundant on overgrazed pastures. However it’s a drought-tolerant and easy-to-grow perennial producing beautiful, flat-topped purple flower clusters in late summer on 3-4’ tall plants – just when the garden needs it. The flowers are favored by many important insects and pollinators. Plant it with the yellows of goldenrod or helenium for a spectacular color combination. If it had a better name, such as “ironflower” or “purple delight” ironweed would no doubt be considered a garden delight.



Ironweed

      Common milkweed (Asclepias syriaca) is valuable as a host plant to numerous important insects including monarch butterflies, milkweed beetles, milkweed bugs and the tussock moth. Though not commercially available, the plant can be easily started by collecting a seed pod in late summer and planting a few of the fluffy seeds where you might desire a little wildness. Another option is to just wait patiently as the plant often comes up freely on its own in many cultivated landscapes. The spicy-fragrant flower balls and young seed pods can be fried as food and Native Americans made a soup from young shoots (properly decanted to remove the milky alkaloids first!).

            Aromatic aster (Aster oblongifolium) is named for the balsam-like aroma given off by its crushed foliage. This bushy plant grows only 18-24” high and is covered by a mass of blue-violet to purple daisy-like flowers in late fall that help give the garden one last splash of interest before cold weather sets in. The plant is becoming common in the nursery trade with many cultivars such as ‘October Skies’ selected and marketed in recent years.