Master Gardeners Educational Activities

Master Gardeners Educational Activities

Brian Jervis: Ask a Master Gardener

Sunday, May 24, 2020

So much of what we do as Master Gardeners involves community engagement. We teach classes, we speak at various civic groups, we have exhibits at community events, we staff our Diagnostic Center at the OSU Extension, and we teach elementary school students about horticultural issues, among other things.

All that came to an abrupt halt a few weeks ago. Like most of us, Master Gardeners have had to learn new ways to help our community during this time.

With so many new gardeners in our midst, we have struggled with how to best help you. Let me tell you a little bit of what we have started to do to help bridge the gap between social distancing and the community needs for horticultural education.

First of all, for kids, we started our new online Fun Pages for Kids. On each fun page, there is a short video, a trivia game, and a coloring page.

We have three Fun Pages currently and hope to release a new one each week, at least through the summer. Current Fun Page topics include one about the lifecycle of Monarch butterflies, honeybees, and worms. The Fun Pages can be found through a link on our homepage: tulsamastergardeners.org.

For the grownups, we have migrated our popular Urban Gardener training classes to an online format for now.

In this series, there are six sessions covering almost everything you need to know to become a more successful gardener. Topics include soil, growing vegetables, pollinator gardens, trees and shrubs, and turf management.

Each session includes an instructional video, links to supplemental materials and additional videos for those who want to dive deeper.

We miss the in-person classes but think these online classes will be helpful for at least the near future.

While the OSU Extension may be closed, soil testing is alive and well with a little bit different process. At this time, soil for soil tests can be dropped off at the extension without human contact.

At the back of the OSU Extension building, there is a black drop-off box with instructions on how to leave your soil sample. We will pick them up and get them to OSU for testing.

It typically only takes about two weeks for you to get your results with recommendations on how to amend your soil properly.

Even though our Diagnostic Center is closed to the public, we are continuing to check the phones for messages and our email account for questions. Each call and email will be answered like always, just not in real-time.

Also, for the next few weeks, we will be live on our Facebook page from noon to 1 p.m. Thursdays to answer your gardening questions. If you are a Facebook person, join us during lunch with a question on the Tulsa Master Gardener’s Facebook page.

We hope everyone stays safe and is using this time to up their gardening game.

Garden tips

·        Clean out water garden and prepare for season. Divide and re-pot water garden plants. Begin feeding fish when water temperatures are higher than 50 degrees.

·        Plant warm-season vegetable crops, such as watermelon, cantaloupe, cucumber, eggplant, okra, sweet potatoes, etc., now.

·        Fruit trees, especially apples and peaches, must be thinned out for best production. Prune apples 4-6 inches apart and peaches 6-8 inches. This will ensure larger fruit and less damage to limbs. If not thinned, the tree's resources will be used to such an extent that next year’s crop will suffer.

Fungal Rust Disease of Pears and Many Other Trees

Rust Diseases on Pears and Others

Tom Ingram: Ask a Master Gardener

Thursday, May 14, 2020

We break from tradition today and are not going to answer a single question but rather address a topic that has been flooding our Diagnostic Center via phone and email: fungal diseases in trees and shrubs. And when I say flooding, I mean flooding.

This spring has been cool and moist for the most part and still is. These are perfect conditions for fungal diseases in plants.

There are a variety of fungal diseases with a variety of names, but in my book, the most interesting one is rust disease. There are several rust diseases: cedar-apple rust, Asian pear rust, cedar-hawthorn rust and cedar-quince rust, to name a few. These diseases are not extremely harmful but can be detrimental to the vigor of both hosts, as well as diminish the productivity of fruiting trees.

One thing that is interesting about these diseases is that they bounce back and forth between different plants with the common link being the cedar (aka juniper). This year, it seems like almost every pear tree in town (including Bradford pears) is covered with Asian pear rust.

While this explanation can seem a little like “which came first: the chicken or the egg,” let’s give it a shot.

The spots we are seeing on pear and apple tree leaves this spring are the result of fungal spores that have blown from a nearby cedar. Nearby is a relative term and typically means within a mile or so, maybe more.

The fungal spots on the apple and pear leaves mature somewhere around June or July. Once mature, they begin to release their own spores, which are then blown by the winds in hopes of finding a cedar to call home.

Asian pear rust causes fairly small rust twig cankers on the cedars, while cedar-apple rust causes small galls to be formed. Fast forward a few months and spring rains cause these cankers to release their own spores, which go out in search of another broadleaf host. Lather, rinse, repeat.

While the Asian pear rust cankers are fairly small, cedar apple rust galls can be golf ball sized. But it gets better. When spring rains soak the cedar-apple rust galls, they begin pushing out these long orange gelatinous tendrils full of spores, which then ride the wind in search of a new home. It is quite a sight.

To control these diseases, the hosts need to be separated, but in town, that is next to impossible. So we are primarily left with treatment options.

Susceptible broadleaf trees, such as apples or pears, can be treated in the spring from the point their leaves emerge through April on seven- to 10-day intervals with a fungicide that includes one of the following ingredients: copper hydroxide, chlorothalonil, myclobutanil and propiconazole (use as specified on the labels). Cedars can be treated in late June-July with the same fungicides. However, you can always physically remove the galls from the cedars when you see them.

For fruiting trees, we recommend you follow a pesticide spraying schedule that can be found in the Hot Topics section on our website, tulsamastergardeners.org.

Garden tips

·        Nutsedge weeds are emerging now. Post-emergent treatments are best applied for the first time this month. Make certain warm-season grasses have completed green-up. Nutsedge control requires specific treatment for control; standard broadleaved post emergent herbicides are not effective. Contact the OSU Tulsa County Master Gardeners for recommendations.

·        Plant summer bulbs such as cannas, dahlias, elephant ear, caladiums and gladiolus.

·        Remember, working wet soil will cause significant damage to the soil structure. Give it time to drain from recent rains, before tilling. Damage from tilling while wet may last for a very long time.

Powdery Mildew Affects Many Plants

Powdery Mildew

Brian Jervis: Ask a Master Gardener

Sunday, May 10, 2020

Q: Some of my plants are developing this white powdery substance on them. What is going on? AM

A: What you are describing is called powdery mildew and can occur on most ornamental plants such as crape myrtles, lilacs, photinias, zinnias, tall phlox, and others. Humid conditions over a variety of temperatures such as cool nights followed by warm days are conducive to powdery mildew growth. Have we been having any of those? Yes, we have. Younger growth also tends to be more affected.

The spores of this disease tend to overwinter on plant debris from the previous season. The spring awakens these dormant spores, which then begin making their way to your new plants. You will likely first notice powdery mildew on the leaves of your plants with them taking on a somewhat dusty appearance.

To prevent this disease from occurring, there are a few things you can do. First, give your plants some breathing room. Do not crowd them. The air circulation will help mitigate the conditions that encourage its development. You may even need to do some pruning to allow for greater air flow.

Also be mindful of when and how you are watering. The leaves of your plant do not need to be watered. The water needs to be placed on the root zone. Now, a lot of times there are sprinkler systems that are watering a large area at once and you cannot keep the water off the leaves. But if you are hand watering, water the roots, not the leaves.

Also, water in the morning. This allows time for water to evaporate off the leaves during the day rather than watering in the evening when water can remain on the leaves all night making a perfect breeding ground for disease.

You also do not want to fertilize your plants in late summer, which would encourage new growth that could become susceptible to powdery mildew.

If these strategies do not prevent development of powdery mildew, your plants can be sprayed with a fungicide or neem oil. Before spraying, remove as many of the infected leaves as is practical. You may say all the leaves are infected. If that is the case, do not remove all the leaves. But if the disease is limited to a certain area of the plant, then by all means, remove that branch or stem because you will be eliminating the source of the problem. You may need to repeat these treatments every two weeks for a while until you don’t see any more evidence of the disease. Chemical treatment will not repair damaged leaves, but it will stop its spread.

Garden tips

• Prune and feed all the spring blooming shrubs, such as azaleas and forsythia immediately after blooming, if needed. Azaleas need less fertilizer than many shrubs and often a yearly addition of mulch, as it decays, it will add all the nutrients they need.

• Seeding and sodding of warm-season grasses such as bermudagrass, Buffalograss and zoysiagrass is best performed in mid-May through the end of June. The soil temperatures are warm enough for germination and growth. These grasses need a long summer growing season to promote winter hardiness.

Mulching Plants is Important

Mulching Plants in your Garden

Tom Ingram: Ask a Master Gardener

Friday, May 1, 2020

Q: I have my vegetable transplants in the ground, now what should I do: DK

A: Congratulations on getting your young veggies in the ground. This is an exciting time. One thing you can do, maybe one of the most important things you can do, is surround them with a layer of mulch. Here is why.

Mulch helps your garden in a variety of ways; one of these is water conservation. A good layer of mulch surrounding your plants will directly correlate to how much time you need to spend watering. Mulch helps hold moisture in the soil by reducing evaporation, and water that does not evaporate is still available to your plants. Seems simple, but you would be surprised how many people don’t do this.

Soil temperature will also be much more consistent with a good layer of mulch. Research has shown that on a hot summer day, the temperature of your soil may rise as much as 30 to 40 degrees, while properly mulched soil temperatures may vary as little as 10 degrees during the same time period. A more constant soil temperature is going to help keep your plants happier and more productive. And to the previous point about water conservation, water evaporation will be much more consequential with a soil temp of 120 degrees than with a more comfortable 80 to 90 degrees.

A mulch barrier between the leaves of your plant and the soil will also help reduce disease. Many of the fungal diseases of vegetables originate in the soil. Without mulch, as it rains or as you water, these diseases can splash up from the soil onto the lower leaves, enabling the disease to find a place to grow. Mulch provides a barrier between the soil and the lower leaves, reducing this splashing and therefore reducing the opportunity for disease.

Additionally, mulch decreases the ability of weeds to grow in your garden because it covers the soil, discouraging those tiny, pesky weeds from breaking through to the outside world. Weeding must be one of my least favorite things, so anything that reduces my time down on my knees in the garden is golden in my book.

There are quite a few options concerning what type of mulch to use. Personally, I mow the leaves from my trees in the fall with a mulching mower. I bag them and save them till now when I can scatter them around my plants. However, I know that ship has sailed for many of you.

The primary recommendation on type of mulch is to use something organic, such as leaves, straw, cotton seed hulls, etc. We say this because most soil in our area is low on organic matter. If you use an organic mulch, it will deteriorate naturally and can be tilled back into the soil at the end of the season. This helps increase the organic matter in your soil, which is always a good thing.

For more information on different types of mulch and best practices, go to the Hot Topics button on our website (tulsamastergardeners.org) and click on the Mulching Garden Soil link.

Garden tips

·        After moving potted plants from inside to outdoors, irrigate the pots with 2-3 pot volumes of water to remove salts that may have accumulated from fertilizers.

·        Spring-blooming bulbs are best fertilized in fall and late winter when leaves emerge. After blooming, they go dormant and cannot use fertilizer applied at that time.