Rodd's Seeds of Wisdom Horticultural tips and tricks from Rodd Moesel

It feels like summer has really arrived in Oklahoma this week.  We have been very blessed so far this growing season with periodic breaks in the heat thanks to clouds, cool fronts and even some rain showers.  This was the first week of pretty much full time, unfiltered bright sun and temperatures in the mid to high nineties every day.  It looks like more of the same in the weeks ahead.  Our early spring plantings have had time to get rooted in and have grown a nice plant canopy and many of our flowering annuals and perennials have been and are blooming nicely this season.  Folks are harvesting their first big tomatoes, cantaloupes and even a few early pumpkins.  This summer weather is a real test for many of our plants as they deal with the extreme heat and dehydration.  Just like we humans need to drink more water and stay hydrated in the heat, so do our plants.  Deeper rooted and more established plants like trees, shrubs and many perennials and native plants can handle the heat and water stress better as they have a larger and deeper root system that can draw in water from deeper in the ground and using a bigger network of roots as “soda straws”.

Annuals and newer plantings that have shallow roots or don’t have as well established of a root system will show the stress of the heat and dry conditions quicker and more often.  We can grow lots of types of plants if we are faithful to take care of their watering needs.  They can grow great corn not just in Iowa, but in Guymon, Oklahoma and even the Arizona desert as long as the growers are prepared to irrigate and provide adequate water to keep the corn from too much stress.  Many plants will tolerate the high light and intense heat as long as they receive adequate water at the right times and don’t become too stressed.  Some plants will visibly wilt, some turn grayish green instead of bright or dark green, and most all will begin to yellow and drop leaves so they have less plant to support if they are under too much heat or drought stress.  Plants under stress become much more vulnerable to pest problems, like bagworms on needle evergreens, red spider mite on tomatoes and marigolds, webworms on pecans, walnuts and other trees.  As soon as you notice these pest problems, get them identified and decide on a course of action.

Help keep your plants summer strong by mulching the soil surface around them 2” or more deep with a good bark or hull mulch.  Water deeply and regularly between rains using drip irrigation, soaker hoses, sprinklers or your water hose.  Every time your plants go to the wilted stage or come under heavy heat or drought stress it saps some of their energy and momentum and acts like a growth regulator.  You surely don’t want to overwater your plants but you don’t want to get them “wilted” dry either.  Some good gardener judgment is involved to know your soil type and water accordingly.   Sandy, well drained soil will dry out more often while clay, tight soils will dry out less often.  One key reason to add sphagnum peat and organic matter to our garden soils over time is that soils with more organic matter will hold more moisture and need less regular or extra watering.  Don’t forget that above ground hanging baskets and container plantings will dry out quicker and will need to be watered more often.

You can still plant in this heat as long as you will be faithful in watering these new plantings.  Like the stories of the cobbler’s kids being the last to get shod we horticulturists are often the last to get our own gardens planted because of being so busy serving others in spring.  Dona and I have done most of our plantings the last two weeks and there may be a little sunburn and extra “heat wilting” for the first few days or even weeks as they adjust to their new home but with adequate water they will adapt well and look great as the season progresses.  You can still plant as long as you will water and mulch!

We have arrived at the midway point of the 2017 calendar and are a little over a third of the way through this growing season.  Time marches on without pause and we are at a point in the growing season where many of our spring plantings are really starting to make a show.  The summer flowering shrubs are producing waves of colorful flowers.  The vitex or butterfly bush is covered with blue flowers.  The crapemyrtles are impressive this year dressed in all tones of pink and red, purple and white flowers.  Crapemyrtles not only produce one wave of flowers but often will bloom repeatedly throughout the hot summer months they love into early fall.  They are available in dwarf varieties that only grow a few feet tall to varieties that make large shrubs or even small trees at 20’ tall or more.  There is a lot of active breeding and variety selection growing on now for new crapemyrtles.  The most prolific breeders are the National Arboretum in Washington D. C. and Lacebark Publications operated by Dr. Carl Whitcomb, right here in Oklahoma at Stillwater.  Gardeners all over the south half of the country are growing new varieties bred and grown right here in Oklahoma.

Other summer flowers putting on a show include the lovely cannas, started from a tuber or purchased as a plant.  These large leaf plants produce impressive flower stalks of red, pink, yellow or orange cannas with either green or reddish foliage.  Many of our perennials bloom now as we enjoy our longest days of the year including white Shasta daisies, Echinacea, gazania, and the impressive Rudbeckia also known as Gloriosa daisy or coneflowers with their exciting yellow and orange flower petals spiraling off the black or brown flower center.  Rudbeckia were first named by Linnaeus and recent breeding has produced lots of stunning choices for your summer garden.

Those of you that are vegetable gardening are now digging your early crops of potatoes and onions.  The tomato plants have really grown over the last few weeks and you should have quite a bit of fruit showing on your tomatoes and may have already had a few fruit  turn red.  Many more tomatoes should start turning red over the next week or two. Green beans and squash are producing their crops while the cantaloupe and watermelon fruit is visible under their canopy of foliage and just needs time and water to product their tender, thirst quenching melons.

Many of the annuals that love the heat are now exploding with color.  Look for lantana, penta, periwinkle, marigolds, zinnia, rose moss, sweet potato vine, copper leaf plant and many other warm blooded crops to respond well to our summer heat.  Even the plants that love the heat the most still need regular and adequate watering to perform well.  Remember your plants can’t turn on or operate the water hose yet so please remember to check your watering regularly and water and mulch your plantings to keep them healthy, happy and growing through our hot and dry summers.  You can still plant container grown annuals, perennials, vegetables, herbs, trees and shrubs as long as you will commit to provide adequate water to get them established.

We continue to be blessed with mild, even beautiful mornings and evenings so this really is a good time to get outside and smell the roses and all your other pretty and amazing flowers and vegetables.  Don’t forget to enjoy the cooling natural shade of your trees in the heat of the day.

Temperatures this week moved into the upper nineties and rain has about disappeared from weather forecasts as Oklahoma looks to have moved into the summer frame of mind.  Fortunately we still have pleasant nights and mornings with those temperatures still touching the lower seventies and giving our plant materials a chance to relax and de-stress during those cooler hours.

The hot, dry weather quickly changes our priorities in the Oklahoma garden.  Watering becomes the most important priority to care for our established plants, the plants we started earlier this spring and particularly any plants we plant now as the weather turns hot.  We lose moisture to dehydration as the bright sun and heat pull moisture from points of high concentration in the plant and the soil.  We lose moisture to hot, dry, blowing winds that visit us regularly in Oklahoma.  When there is no natural rain to replace this moisture, your trees, shrubs, vegetables, flowers and lawn become dependent on you to keep them in a healthy, growing condition.  Many plants will survive through the hot dry weather but make adjustments to stay alive.  As they stop growing they will wilt, get a grayish tone to their color and will shed leaves to reduce their “plant operations” to the available moisture.  Those things happen if you do not water sufficiently to keep them in a healthy vegetative state.  It causes great harm to most plants to get excessively dry or to go through extreme wet/dry cycles.  Watering needs vary a lot depending on your type of soil, amount of organic matter in the soil, whether the plants are in full sun, shade or partial sun.  Other factors are whether plants are planted alongside concrete walks or driveways, in front of concrete or metal walls, growing in a container or in a ground flowerbed, in the wide open or a wind protected microclimate.   Do you water by hand, drip or sprinkler and are the soil surfaces mulched or is there bare soil exposed to the sun’s heat and our blow dryer winds?

Giving your plants sufficient water keeps the plants in “go” mode, growing larger canopies, producing flowers, veggies, fruit and nuts.  Heat stress and drought is like throwing up a stop sign and causes the plant to reduce operations and growth to the available water.  Many plants will bounce back from one or several heat stresses or wilting but repeated stresses can kill or stunt plant development.  Pull or remove weeds that compete with your chosen plants for precious water resources, mulch the tops of your container gardens and flowers beds with two or three inches of bark or natural hull mulches and consider installing drip irrigation or using soaker hoses.  When you water, soak good so the water penetrates several inches down in your soil.  It is better to soak one to three times a week depending on your plants and soil type rather than to spray or squirt the plants every day.
Besides watering and weeding, this is the season to be alert for insect problems.  We usually see fewer fungus and diseases problems in the heat but we see an increase in insect problems as most insects lay many more eggs in hot weather and more often so populations can appear to explode.  Be on the lookout for aphids, mealy bugs, spider mites, bagworms, webworm and other unwanted insect challenges.  You can identify them using garden books, the internet or take a sample in a sealed plastic baggie or paper bag to your local garden center.  They can help you evaluate control choices whether you want to look at organic or chemical options.

The season finally slowed down a little so while many of your are digging potatoes and onions and preparing to pick your first squash, cucumbers and tomatoes we are finally getting to plant our tomatoes, peppers and lots of pretty flowers.  You other procrastinators can join us in planting now as long are you remember to water regularly to help these new plants get well established.