Irrigation can’t replace rain

You’ve seen it. The luminous post-shower greenness of a lawn; the sudden growth spurt of a plant that didn’t seem to be doing much at all; or the effervescence of new blooms on an otherwise sleepy plant. Why are these effects so evident after a good rain and absent with irrigation?

What’s the magic of rain? It’s all about what it has that tap water doesn’t,  and what it doesn’t have that tap water does.  And this all boils down to chemistry.

Rain water is free of minerals

good elements

Rainwater lacks the minerals usually found in irrigation water. In The Woodlands, the water that flows through an outside spigot is the same as what flows from the kitchen faucet—that is, treated water suitable for consumption. This is of course, what you want for water use in the home, but your landscape can actually suffer for it when used in excess.

Chlorine and fluoride are the first plant-offending additives in treated water. Chlorine is a necessary disinfectant and fluoride helps to prevent tooth decay.  But nearly all plants are susceptible to chlorine toxicity and many are subject to fluoride toxicity as well—especially common house plants.

Another chemical component to tap water is sodium, which can help remedy the pipe-corroding effects of calcium and magnesium, also present. When a white sediment is present on the outside of containers or on the leaves of plants, it’s evidence of calcium and magnesium. Sodium, like chlorine, is toxic to plants.

Rainwater has the right stuff

good elements

Oxygen, nitrogen, and carbon dioxide. Rain highly saturated in oxygen goes right to the roots that take up this vital element. Nitrogen is what makes your lawn and plants seem to glow green after a good rain. Air is 78% nitrogen and this element in its nitrate and ammonium forms comes down in rain and is immediately absorbed by plants through their roots and leaves.

Carbon dioxide is also delivered to plants with rain. When carbon dioxide combines with other minerals in the air, it gives rainwater an acidic pH. Acidic rainwater (and we’re not talking about “acid rain” which has excessive pollutants mostly an issue in the Northeast) helps the soil release essential micronutrients such as zinc, manganese, copper, and iron that are vital to plant growth.

rose-2658659

Something can be said about the physical properties of rain too.

Rain penetrates the soil better than irrigation. Raindrops fall at about 20 mph while irrigation droplets fall at about 5 mph. And rain falls uniformly. Both properties help water reach plants’ roots. And they do something else: they help leach salts away from the root zone of a plant where they may have accumulated over time through irrigation. This cleansing effect can have a pronounced effect on new plant growth.

The cleansing effect of rain extends to the entire surface of a plant as well. We can see how foliage glows after a rain washes away mineral deposits, dust and pollutants from leaves. This is a boon to photosynthesis. Photosynthesis is much more efficient when light reaches a plant’s leaves unobstructed by grit and grime.

Harvest it

The benefits of rain water over tap water used for irrigation might even motivate a person to harvest rainwater. So often, rainwater harvesting is presented only as a method for conserving water. Yet it’s more than that. By storing up rain water, you’re also creating a supply of high quality water that your plants crave.

A Drip Irrigation and Rainwater Harvesting class will be offered free by the Township later this spring.

OE and tropical milkweed

The relative virtues and problems associated with tropical milkweed, Asclepias curassavica, continue to be a hot topic within the monarch conservation community, but the disparity between the two is becoming more and more clear. Scientific research suggests that its problems, namely its link to the spread of the Ophryocystis elektroscirrha (OE) disease, far out-weigh its virtues. In fact, it’s those very virtues—availability, adaptability, and long bloom season—that multiply its negative effects relative to the health and sustainability of the monarch butterfly species.

What is OE?

OE is a protozoan parasite that infects butterflies that host on milkweed. Its life cycle starts as a microscopic spore that breaks open when ingested by a caterpillar. Within the caterpillar, it grows and multiplies. Because a parasite depends on its host for its own life, OE rarely kills the caterpillar.

scales and spores

OE spores are only visible under a microscope.

But the disease affects the development of the adult butterfly while pupating, and adults emerge weak and often with crippled wings. While many monarchs may carry OE as spores attached to its wings and thorax, the size of the spore-carrying population and the heavy level of spores within that population in the Gulf Coast region—especially Texas and Florida—is cause for alarm. Visit Project Monarch Health for more about OE.

oemonarchemergetwo6

An adult butterfly with OE has no chance of survival when wings are malformed.

Recent studies corroborate earlier studies and tighten the link between tropical milkweed and an increase of OE. Gardening to help conserve monarchs requires an understanding of the risks associated with tropical milkweed as well as the steps to take to minimize its ill effects.

The introduction of tropical milkweed in the U.S.

Monarch enthusiasts with the best intentions were thrilled when local nurseries began to offer tropical milkweed for sale and embraced the Mexican native with gusto. It didn’t take long to discover that aside from being very easy to grow, monarch butterflies love this variety of milkweed. It seemed that a solution was in hand to help restore milkweed habitat for the Eastern migratory monarch population. As a result, tropical milkweed has been well established in parts the southern states—especially southeast Texas and southern Florida.

Then research began to emerge that showed an increase in monarch disease caused by OE was linked to tropical milkweed grown in the southern states.

What the research shows is particularly troubling for the monarch migration that passes through Texas gardens to feed and breed.

The effects of tropical milkweed

Research by Karen Oberhauser, Dara Satterfield, and others has and continues to demonstrate that OE in monarchs increases where tropical milkweed flourishes. (See links to studies at the end of this blog.)

What’s been determined is that the proliferation of tropical milkweed (in the southeastern parts of Texas and south Florida in particular), coupled with its near year-round foliage and flower production does two things:

It interferes with the monarch’s migratory cycle. Tropical milkweed encourages them to linger in the southern states and continue breeding and laying eggs, “trapping” them here where they cannot survive temperatures that drop toward the freezing mark. Possibly more important is the effect of milder winters. Given a non-stop supply of milkweed, interference with normal migratory behavior produces populations of monarchs that overwinter in Texas and Florida instead of completing their migration to the oyamel fir tree forests of central Mexico.

Monarchs who stay in the southern states for the winter are five to nine times more likely to be infected with OE than migrating butterflies.

It significantly increases the rate monarchs are infected by the debilitating OE protozoan pathogen. If mild winters don’t produce a freeze, infected milkweed continues to thrive, not dying back like native milkweed species. This means infected plants persist. Infected plants in Texas are especially harmful because they sit in the gateway for the spring and fall monarch migrations.

Migrant butterflies at sites with overwintering residents were 13 times more likely to have infections compared to migrant populations that don’t come in contact with residents.

Adult monarchs migrating from Mexico in the spring that visit infected plants pick up hundreds of OE spores and carry them to other plants—increasing the number of infected plants and as a result butterflies, exponentially.

What to do?

If there’s any good news in this it could be that originally, most of the tropical milkweed planted was done so in gardens. By definition, gardens are tended. Gardeners should consider taking one of two actions.

Replace tropical milkweed with native species. While native varieties are more challenging to start, the effort would help minimize the spread of OE. Try these native species:

  • Asclepias incarnate, Swamp milkweed
  • Asclepias perennis, Aquatic milkweed
  • Asclepias tuberosa, Butterflyweed
  • Asclepias verticillata, Whorled Milkweed
  • Asclepias viridi, Green milkweed

Or, be diligent about cutting it back every winter. Cut tropical milkweed plants to within four to six inches of the ground each November.

If you have tropical milkweed in your garden and didn’t cut it back in November, do it now.

Milkweed for habitats

Milkweed used for non-gardening purposes poses a more clear guideline. Dara Satterfield  recommends, “that habitat restoration for monarchs focus on native species of milkweed, which are synchronized with the monarch’s natural migratory cycle and do not enable the year-round breeding that can lead to high parasitism rates.”

The spring migration approaches

Tracking the spring monarch migration starts on February 14. Visit Journey North to learn how you can enter your own monarch sightings and track the migration real time.

Delve in and learn more about tropical milkweed and its effect on the health of monarchs with these recent studies:

Patterns of parasitism in monarch butterflies during the breeding season in eastern North America, Ecological Entomology, 2018

Migratory monarchs that encounter resident monarchs how life-history differences and higher rates of parasite infection, Ecology Letters, 2018

Monarch butterfly migration and parasite transmission in eastern North America, Ecological Society of America, 2011

Loss of migratory behaviour increases infection risk for a butterfly host, The Royal Society Publishing, 2015

Learn more about native milkweed species at these resources:

Native Plant Society of Texas

Ladybird Johnson Wildflower Center Plant Database

PDF of Identification of Milkweed in Texas, by Texas Parks & Wildlife

Healthier lawns, cleaner streams

One thoughtful action can help promote both: Think before you fertilize. All too often, lawns are fertilized too heavily, at the wrong time, or when they don’t need it at all—thanks to the formidable marketing efforts by fertilizer companies. Instead of automatically reaching for your spreader, consider what your lawn really needs and the consequences of over-fertilization.

blade-blooming-blossom-5865

Know what your lawn needs

Timing. The time to fertilize a lawn is when it’s growing more roots than blades; and to know when that is, know the type of grass in the lawn. Grass can be categorized in two ways: warm-season or cool-season. These terms refer to the weather in which the grass has adapted to grow. Turf grasses most common in our area, St. Augustine, Zoysia and Bermuda, are all warm-season grasses and start their growth in spring, making that the best time for fertilization.

Fall is when these grasses go dormant making fertilizers moot. Fertilizing at the wrong time can actually be harmful. Feeding your warm-season turf nitrogen in fall can force new top growth making the lawn susceptible to frost, shock and disease. What’s more is that this takes away energy from root growth, leading to weak, thin lawns.

No matter what, always follow a fertilizer’s instructions exactly when it comes to application.

Test it. Having said all this, don’t assume you need to fertilize every spring. The only way to know what nutrients your soil is lacking is to have your soil tested. Instructions for how to take a soil sample and the form for sending it to Texas A&M for analysis can be found with this link: Soil Test Form.

Go organic. If you find your soil needs supplemental nutrients for turf grass, consider using organic instead of synthetic fertilizers. Unlike synthetic fertilizers, organic fertilizers don’t create high levels of salts which kill beneficial soil organisms—the key to good soil health. And organic fertilizers work slowly, wasting nothing. They also improve soil texture making it easier for air to get to the roots and helping the soil retain water longer.

Organic forms of fertilizers include:

  • Alfalfa meal
  • Bat guano
  • Fish emulsion
  • Cotton seed meal
  • Seaweed
  • Manure
  • Compost

Refer to Best Organic Fertilizers for a full list of organic fertilizers and what they specifically offer.

How does this affect the quality of streams?

When quick-release synthetic fertilizers are over used, the chemicals are washed from our lawns in a downpour. The polluted run-off is channeled into the nearest waterway via storm drains, untreated and unfiltered. This water in turn contaminates our creeks, rivers and groundwater. High concentrations of nitrogen in water can also lead to an algae overgrowth, threatening the health of aquatic life.

Pond-LVphoto

Currently, over 80% of waterways in Texas are listed by the Texas Commission on Environmental Quality as “impaired,” creating poor habitat for aquatic organisms such as fish and turtles. High bacteria levels are another culprit and may lead to restrictions on water-contact recreation, such as  swimming and wading, fishing, and kayaking.

Other ways to help keep our water clean:

  • Pick up pet waste—it’s the number one source of bacteria in our waterways.
  • Maintain cars so they don’t leak oil and other chemicals onto driveways.
  • Compost, compost, compost.
  • Never flush unwanted or out-of-date medicines down the toilet or drain.
  • Minimize areas of turf grass and pavement while increasing areas of native plants
  • Install a rain garden

For more information about lawn care, download Guide to Yard Care, by Texas Commission on Environmental Quality.

To learn more about water conservation in The Woodlands, visit The Woodlands Township’s Water Conservation webpage.

Water Conservation Yard Sign 3

The great pumpkin

It’s an iconic symbol of the season. Porches, lamp posts, benches and steps are decorated with pumpkins—they are so ubiquitous that today 80% of the pumpkins grown in the U.S. are available in the month of October alone.

jack-o-lantern-3735387

The jack-o-lantern

For Halloween, these orange orbs are often carved with ghoulish faces illuminated with candles to the delight of children and adults alike. Originally known as jack-o-lanterns, we have the Irish to thank for this tradition that has folded into the fabric of our holiday. But the original jack-o-lantern wasn’t carved of pumpkin—pumpkins didn’t exist in Ireland. Ancient Celtic cultures in Ireland carved turnips. On All Hallow’s Eve, the Irish placed an ember in them to ward off evil spirits. The lore behind this tradition is the Irishman, Stingy Jack, who bargained with the devil and was doomed to roam the Earth with only a hollowed turnip to light his way.

There are other ways to use pumpkins as festive decoration. Use them as planters and set your Thanksgiving table apart.

History of the pumpkin in the Americas

There is more to the history of pumpkins to appreciate. One of the oldest known food crops in the western hemisphere, pumpkins are native to parts of the southwestern U.S., Mexico, Peru, Ecuador and Colombia. Pumpkins are known to have been cultivated since about 3500 BCE. Some archaeological evidence shows that ancient Aztecs used pumpkin seeds as a quick energy snack. Native Americans roasted long strips of pumpkins over a fire and also dried pumpkin, weaving the strips into mats. Throughout South and Central America pumpkin pulp has long been used as a treatment for burns.

When European colonists arrived in the New World, they relied heavily on pumpkin as a food source. Colonists prepared pumpkin by cutting off the top of the fruit, removing the seeds and pulp and replacing them with a mixture of milk, spices and honey. This food was the origin of the pumpkin pie enjoyed today.

flower-954484

Growing pumpkins

Cultivating pumpkins in the southeast Texas home garden is possible, although challenging. Pumpkins are heat-loving plants with seed germination dependent upon warm soil. In Montgomery County, late March to early April is the optimum planting time. Pumpkins require a day time temperature of 85-95 degrees with a night time temperature range of 60-70 degrees.

When preparing the garden for pumpkin growing, apply a generous amount of high quality compost to provide the nutrition requirements of these heavy feeders. Select a location with well-drained soil and few weeds, and select a pumpkin variety that’s small or dwarf since the large-fruited varieties require a space at least 18 feet in width and length for the vigorous vines. Smaller pumpkin varieties can be successfully grown in a space with plants two feet apart and rows 6 feet apart. If space is limited, you can even grow them in a pot.

Since pumpkin is a member of the cucurbit family, it’s susceptible to the same pests and diseases which plague squash, cucumbers and other cucurbits. Insect pests include:  squash bugs, squash vine borer, cucumber beetles and aphids. Plant diseases include powdery mildew, leaf spot, black rot, gummy stem blight, mosaic virus and bacterial wilt. Our local, frequently damp climate provides perfect conditions for these diseases. Removing plant debris and careful tool cleaning and sanitation will help prevent disease. For high quality fruit with a long life, harvesting at maturity is crucial. A pumpkin is mature when the entire shell has developed uniform hardness.

pumpkin-soup-3705294

Cooking with pumpkins

A versatile fruit for culinary endeavors, pumpkin lends itself to preparations ranging from soups to pies and breads. No wonder the pumpkin has found its way onto the Thanksgiving table. For inspiration in the kitchen, see these pumpkin recipes  from Fine Cooking.

Nutritionally, pumpkin is a powerful food which is low in calories and fat but high in fiber, Vitamin A, Vitamin B, potassium, protein and iron. One cup of cooked pumpkin contains only 49 calories. Since every part of the pumpkin is edible, experiment with preparing not only the pulp but also the seeds, flowers, leaves and stems. Check out these guidelines for processing pumpkins.

Add beauty and manage rain with a rain garden

Rain gardens are simple landscaping features used to slow, collect, infiltrate and filter storm water. They offer a great way to turn a landscape “problem” into a real benefit. Rain gardens are planted areas—best added to a low lying area that collects rain water—that include deep-rooted native plants and grasses that are designed to thrive in wet soil, soak up excess rain water, and withstand intermittent dry periods.

There are aesthetic benefits to rain gardens as well, transforming a bare, wet area into a green, blooming habitat that provides food and shelter for birds, butterflies, and other wildlife. Amphibians such as frogs and toads will be attracted to this naturally wet area.

The problem

Increased stormwater runoff is the real problem. Add soil erosion to that and the result is vulnerability to flooding. Rain gardens help prevent both, helping to conserve water and soil.

Water Cycle

Consider the water cycle shown above and then add human development to the picture. Humans create stormwater runoff when natural areas are developed, replacing them with a sea of impervious surfaces fragmenting our green spaces.  Within a developed residential area, pollutants such as fertilizers, herbicides, pet waste, and oil are washed from lawns, streets, and parking lots into local streams and drainage systems.

Polluted runoff is the number one water
quality issue in the United States. 

How rain gardens help

While a single rain garden may seem inconsequential, it has great value, and several in a neighborhood collectively can produce substantial benefits. They slow the water down and let it collect in the garden’s depression, settling soil, silt and organic material that are washed by the water from higher ground. Water slowly filters back into the soil where it is needed most.  The deep rooted plants and grasses in the rain garden hold of the soil, keeping it in place. Rain gardens can also be designed to divert run off from sewer systems.

Plants within the rain garden increase the infiltration of water, giving the natural process that removes pollutants time to do its work. Naturally purified water then recharges the groundwater system. The end result is that by adding a rain garden to the landscape is a strategy that makes a difference.  Flooding is reduced.  Pollutants are filtered from the water. Runoff is diverted from streets and storm sewers.

Concern that a rain garden might serve as a breeding area for mosquitoes is not valid when they are sited correctly. Following a rain, ponding should last no longer than approximately 72 hours. This is a much shorter time frame than the 7 to 14 days required for most species of mosquitoes to develop and hatch from eggs laid in standing water.

texas rain garden

Rain garden basics

Choose a site. Locate your garden in a low lying area of your landscape that tends to collect rain water at least 10 feet from your foundation. Choose a sunny or partially sunny spot. Also consider how it can be incorporated into your existing landscape replacing an area of traditional turf grass where the lawn slopes toward the street. An area that would catch roof run off or water from a down spout is perfect. If the rain garden is located on a slope, create a berm on the low side to retail water and soil.

Compared to a patch of lawn, a rain garden allows 30% more water to soak in the ground.

Test drainage. Test the location’s drainage before you create the bed. Dig a hole 8 to 12 inches deep and fill the hole with water. The water should soak in within 48 to 72 hours. Soils heavy in clay will drain much more slowly than soils heavier in loam, silt or sand. Amend sites heavy in clay with organic compost to improve the soil and help drainage. If the site doesn’t drain within 72 hours, choose another site.

Start digging. Rain gardens can be any size, but a typical residential rain garden ranges from 100 to 300 square feet. The depth of the garden can range between four and eight inches. Anything too deep might pond water too long and if too shallow, it will require greater surface area to effectively manage water.

Add plants. Choose a variety of native forbs and grasses, planting those with higher water tolerance in the middle of the garden. Include plants of varying heights and bloom times to maximize the garden’s depth, texture and color. Plant in groups of three to seven plants of a single species.  Go for diversity. In natural areas, a diversity of plant types not only adds beauty, but also creates thick underground root network that keeps the entire plant community in balance.

The chart below includes plants for our area suitable for a rain garden. Planting zones are indicated as:

Margin: the high edge around the rain garden that is the driest zone
Median: the area between the margin and center
Center: the middle of the garden that is deeper and will stay wet longest

Rain garden plant listHelp it flourish. Rain gardens can be maintained with little effort after plants are established. Weeding and some watering during dry periods will be needed the first two years.

Attend the upcoming rain garden class

Join Patrick Dickinson, Texas A&M Water University horticulturist on Saturday, October 27, 2018 from 9:00 a.m. to noon as he presents Gardening 102:  Rain Gardens.

Register here.

Resources

Refer to Harris County AgriLife Extension gardening fact sheet, Rain Gardens, for more details about planning a rain garden and for a full plant list.

Check out WaterSmart, a presentation by Chris LaChance of Texas AgriLife Extension, for good information and nice photos of various rain gardens.

This how-to manual on Rain Gardens by the Wisconsin Department of Natural Resources may have plant lists that aren’t suitable for this area, but it’s a good guide to creating a rain garden no matter where you live.

Grow a native American vegetable and treat your landscape and palate alike

Helianthus tuberosus

Cultivated for centuries prior to the arrival of European explorers and settlers, our country’s only native vegetable is also a Texas native sunflower. The “jerusalem artichoke” or “sunchoke” is the enlarged underground stem of helianthus tuberosus, a type of sunflower in the aster family with edible tuberous roots. While commonly regarded as native vegetables, potatoes, tomatoes, corn and peppers all originated either in Central or South America.

20121210-sunchoke-kenji

Today, we take the food on our plate for granted, but the History of Vegetables  is a fascinating study.

The common name “Jerusalem artichoke” is likely a corruption of the Italian girasole (turning toward the sun) which is a trait shared by all sunflowers. In more recent years, the edible tubers of helianthus tuberosus have become known as “sunchokes”.

Sunchokes have a delicious, sweet nutty taste.  As an extra bonus, these tubers are nutritious and an excellent source of iron, potassium and fiber.

The original distribution of this native Texas sunflower is unclear because the plant was transported to many different geographic locations for cultivation by Native Americans.  Today, helianthus tuberosus can be found along the edges of wooded areas, in former fields and along roadsides.

Helianthus tuberosus

This showy sunflower is also sometimes grown simply for its bright yellow blooms and tall, fast growing stems. Broad, thick leaves and rough hairy stems add to the visual attractiveness of this native plant.

Blooming in late summer and early fall, helianthus tuberosus requires full sun to part shade. A tough and versatile plant, this sunflower will grow in moist or dry soil and tolerates drought, heat and frigid temperatures. Because of these qualities, it’s very easy to grow. Helianthus tuberosus is extremely useful in the garden where it can quickly become a temporary summer screen, a stunning background for a native plant border or the sunny edge of a natural wooded area.

Nectar source for butterflies

This particular sunflower is beneficial for both insects and wildlife. The large yellow flowers offer nectar for butterflies, pollen for bees while also supporting many predatory and parasitoid wasps, flies and beetles. In fall, the seed heads attract birds while the large plants offer cover for small wildlife.

Beekeepers have noted that helianthus tuberosus  is an excellent honey plant resulting in a clear amber product when harvested.

Very little is known about pests or diseases which damage this plant. It appears to be quite resistant, which contributes to its easy to grow nature. In the southeast Texas climate, the optimum planting time is early spring with the main harvest in fall. Since helianthus tuberosus is a perennial plant, once started in the garden, it’ll return each spring from tubers left in the soil.

Growing helianthus tuberosus in your garden or landscape offers new opportunities for applying culinary skills as well as providing beauty, food for pollinators and cover for wildlife.

The edible tubers or sunchokes can be harvested beginning within two or three weeks after the flowers fade. Harvesting can continue after the first freeze damages the stems and leaves of the plant. Each plant will produce approximately 2-5 pounds of sunchokes. When left in the ground after the first frost, the tubers become sweeter and crispier. To preserve the freshness, store sunchokes in a zip top plastic bag in the refrigerator. This strategy preserves the tuber’s natural moisture.

While sunchokes are frequently used in cooking as a potato substitute, unlike potatoes, they can be used raw and add a nutritious crunch to salads. Sunchokes are also an excellent vegetable for pickling.

If you like to get even more creative in the kitchen, try Pan-Roasted Sunchokes and Artichoke Hearts with Lemon-Herb Butter.

Looks and sounds delish.

pan-roasted-sunchokes-artichoke-hearts-recipe-main

For more information on the nutritional value of various foods, check out this nutrition guide, by the USDA.