Dan West Garden Center

July 2008 Newsletter©

More FAQs

This month we are taking questions from the class.  I may, from time to time, answer questions we’ve covered before for the benefit of the new gardeners that have just joined our class and for those of you who just weren’t listening the first time!  So, what’s happening in your garden?

I have what looks like yellow foam growing in my flowerbed.  What is it?

It’s a slime mold.  Isn’t it cool!  It grows on wood chips which it digests for the carbon.  It grows rapidly, eventually turning a little pink and then dark brown. It’s not harming anything unless you allow it to grow over and shade low growing plants.  When you see it start, just blast it apart with the water hose.  (More correctly it’s known as “dog vomit slime mold” and if you’ve ever seen it, you know why.)

I have this white stuff growing on the soil in my houseplants.  Is it a slime mold? 

It’s not a slime mold, but it is a fungus.  Most potting soils have some bark mixed in.  Wet bark is an ideal place for fungus to grow.  Usually these are harmless but may add to your allergy problems.  Scratching the soil surface frequently, will help control it or a soil drench with a fungicide may be necessary.  Covering the soil surface with pea gravel helps prevent the spores from being stirred up when you water.

Is that the white crusty stuff on my clay pots?

No, that’s salt.  Salt forms from fertilizer and water. If it accumulates on your pots, it’s also accumulating in your leaves and can cause brown leaf tips and margins.  You can get most of it out of your soil by setting the pot in warm water up to the rim. Then pick it up and most of the salt will be pulled out with the water that drains.

Should I repot my plants if I have salt buildup?

I’d slip the plant out of the pot and wash all visible salt off.  I wouldn’t repot,  unless you need to.

How do I know if I need to repot my indoor plants?

There are a couple of ways to tell.  If it needs watering everyday, then the roots have filled the soil mass and I’d repot.  Another way to tell is to take a pencil and try to push it, eraser side down, into the soil.  If it’s easy to push an inch deep, then you don’t need to repot.  If you can’t, try another spot and if  you still can’t push it into the soil, then repot. 

There are two important rules when repotting. First, try to match the type soil you already have.  Does it have bark, peat moss or perlite?  The closer the two soils match, the easier it is for roots to penetrate the new soil and the less watering problems you’ll have.  Different soil types dry at different rates.  Your original soil mass (that’s full of roots) will dry at a different rate than the new soil around the edge of the pot, even if you use the same soil, so water carefully.  Second, don’t increase the pot size more than 2-3 inches.  The wider the new soil layer in the pot, the more difficult it is to water evenly.

I’d also get a long screwdriver and poke a few holes in the existing rootball so water penetrates the center and is not just running around the outside of the rootball.

I’ve had a problem with fungus gnats in my containers.  How can I get rid of them?

Normally fungus gnats are just a nuisance.  The larvae, a maggot, feeds on decomposing organic matter in the soil.  Occasionally the population is high enough that they feed on root tips and actually damage plants.  The adults are attracted to light where they can be easily killed with any flying insect killer.  Then treat with Bonide’s Houseplant Insect Control that contains Imidacloprid.  It controls fungus gnat larvae as well as aphids, mealybugs, whiteflies and scale insects for about 2 months.   Not for use on veggies and herbs, just container ornamentals. 

Since we’re talking about container plants, what fertilizer should I  use and how often?

On annuals that grow rapidly and bloom continually through the summer such as impatiens, begonias or lantana or tropical plants like mandevilla and hibiscus, apply a 3-4 month timed release fertilizer  (ferti-lome Start-N-Grow) at planting and supplement with a water soluble spray feed (Blooming and Rooting) every 2 weeks.  A lot of water and nutrients flows out the drain hole so don’t be afraid to fertilize.  When you fertilize container plants, you just need to mist the foliage and spray a little in the container. If it’s dripping off on the deck, you are wasting product…and money!

For indoor plants that aren’t watered as often, use an organic like Sea Tea or fish emulsion once a month from March through September.

Should I fertilize my annuals planted in the ground the same way?

Yes.  If you want the most flowers and growth out of your annuals, spray feed them every two weeks with Blooming and Rooting fertilizer.

What USDA zone are we really in?

It depends.  Below is the 1990 USDA Hardiness Zone Map. According to it, we are zone 7.  In fact, on a more detailed map, the dividing line between zone 7A and 7B (a 5° average temperature difference) was the Wolf River.

In 2003, a new map was commissioned that took into consideration heat islands of the cities and another 10 plus years of average temperatures, which have been warmer.  Three years and who knows how many millions of dollars later, we have the new map…

And now…Shelby County is in Zone 8.

Plants that we considered borderline hardy in the 1970’s have done quite well here lately.  Old zone 8 variety gardenias haven’t been severly damaged here in several years  (now we have gardenias that are zone 6 hardy).  Indian hawthorn (Raphiolepis) and sweet olive (Osmanthus fragrans) were not considered hardy, but they have been recently.  I have an Asparagus meyeri (foxtail fern) planted next to my front walk that has come through the last 5 winters and it’s a zone 9 plant. 

So I feel comfortable planting any zone 7 and most zone 8 plants if they are put in the right place…out of the wind, and where the soil is likely to be sun/wall/concrete warmed during the winter.  Let’s face it, outlying areas are probably still zone 7 and even if we are zone 8, we are at the far north end.  We will, at some point, have another crape myrtle killing winter like we had back in the 80’s.

At the same time our warmer summers and winters have made it easier to grow some plants, they’ve made it more difficult to grow others.  Dwarf Alberta (as in Canada) Spruce have always been difficult to grow but they are becoming even more so.

You mentioned gardenias. My neighbor and I both planted August Beauty gardenias.  Her’s is beautiful, mine died last  winter.  Why?

We live in what’s called “the transition zone”.  Our soil freezes and thaws repeatedly each winter.  When the soil temperature drops below 45°, plants stop absorbing water.  Plants that have green stems (like gardenias) can be dessicated by wind if the soil temperature remains low for long periods of time. It prevents the plant from re-hydrating itself.  Extremely low  temperatures can cause the wood to freeze and split. As the temperature rises, food produced in the foliage can’t get to the roots and the plant dies or is killed back to the ground.

New plants, that haven’t developed roots into the surrounding soil, get all their moisture from the bark based soil they were grown in.  It dries much faster than your clay, so it’s more likely to be damaged by cold, windy conditions than an established plant.  Soil temperature, soil moisture, exposure to wind and sun, amount of foliage, depth of mulch, all are variables that contribute to the success or failure of a new plant and the conditions may vary on two plants, side by side.

So why did yours die?  I’ve said it before and you’ll hear it again and again and again…

No plant wants to die before it’s time.  If a plant dies suddenly, new or established…it either got something it didn’t want or it wanted something it didn’t get.  There is no third alternative.

Usually it’s a watering or insect or watering or disease or watering or sun or watering or shade or watering or location or watering\drainage problem.

Next question?

My tomatoes are turning black on the bottom.  I’m spraying mancozeb for early blight, but it’s not stopping this!

That’s not a fungus problem.  It’s called blossom end rot.  We see it on tomatoes, peppers, squash and watermelons.  It’s actually a calcium deficiency and can be cleared up quickly with Yield Booster, a liquid calcium choride product.  Remove any blackened fruit.  There’s no point in the plant wasting any energy on bad fruit.

I was watching a gardening program the other day and the expert recommended cypress mulch, peat moss, high nitrogen fertilizer and something called "expanded shell" to plant azaleas.  What is expanded shell?

"Expanded shell" is a term for man-made aggregates primarily used to make lightweight concrete.   Do you need it?  Probably not.
When planting an azalea (or any plant), the ideal product to use is a blend of what the plant is currently growing in and your soil.  This gives the roots the best transition area.  Most azaleas are grown in a pine bark based mix, so use finely ground pine bark at about 1/3 bark to 2/3 of your soil.  Make sure the plant is elevated at least 2" above your soil line.  Bring the blend up to, but not on top of the rootball so it looks like it's planted on a little hill.  Pine bark has a little calcium in it, so it may raise your pH a tad, but if you are using a well balanced azalea food (not just nitrogen), it will offset any pH change. You can add a couple of inches of coarse cypress (or any) mulch on top after planting. 

Pine bark soil additive is usually cheap and readily available.  Blend a little cotton burr compost with it and you really don't need the aggregate and I’m not a big fan of peat moss either.  If you still want to try an aggregate, we sell a coarser product called Soil Perfector which will do the same thing.

Dr. Carl Whitcomb has done a lot of research on soils and additives. Basically his conclusion was loosening the soil is the most important factor when planting.  What you add as an amendment isn't nearly as important.   But in nature, top soil is made from leaves, bark, sticks, some blown in dust and minerals, decomposed annual vegetation roots (which helps loosen the soil) with a little help from earthworms, fungi and a gazillion microbes.
This system works pretty well.  So it seems to me, since bark is cheap and readily available, we should copy the process. 

How often should I lime my lawn?

I’d check the pH first, but probably every other year if you are fertilizing two or more times per season. At a pH of 6.5, you get maximum availability of all major and minor plant nutrients.  If you allow it to fall to 5.5, many minor elements become less available as they lock up it forms unavailable to the grass.  Liming is the cheapest and best thing you can do for your lawn. A 40 lb. bag of pelletized lime should be applied to 1000 sq. ft. to raise your pH about one half point.  Cheaper still is Fast Lime.  A 30 lb. bag covers 5000 sq. ft. 

Don’t forget, you can ask a question anytime on our website.

www.danwestonline.com/question

This was last month’s mystery plant.  The plant is Deutzia “Pink-A-Boo” and we had one, just one, correct answer.  I planted a 5 gallon size plant 5 years ago in my backyard.  It is over 6’ tall and 8’ wide and is loaded with flowers in May. It is a weeping deciduous shrub, so it’s not for people that have evergreen mentalities.  It is spectacular when in bloom.

For July, I’m going to make the contest a little easier.  Here’s the plant.  What is it?  Your answer must be one word.  I’ll accept the genus or the common name.  One word. 

The contest ends on July 15^th.  Drop by either store to enter or you can email your entry to questions@danwestonline.com.  One winner, selected from all correct entries, will receive a $25 Dan West Gift Certificate.

See you next month!  And we sincerely thank you, for shopping with us at Dan West.