Archives September 2007

It’s getting to that time of year when we have frost warnings. Last night and the night before were such cases. We have learned through hard lessons to err on the side of caution when it comes to a frost.
Frost occur when the temperature falls below freezing, usually at night. The frost is sometimes evident in the early morning light as a white “frosty” covering on the grass and other vegetation. This is not to be confused with a hard freeze. A hard freeze will cause damage to plants left anywhere outside, even of covered.

Tender plants such as impatiens, geraniums, and tropicals like the elephants ears, Boston ferns and vegetables like tomatoes and peppers are susceptible to frost damage. The freezing air causes leaf damage as the cells rupture when frozen. If you have ever left a can of soda in the refrigerator you will know what happens. The liquid expands when frozen and with the case of plants the cell membrane is damage and the cell dies.

Since the annual plants get their energy from the leaves the plants die.
Perennial plants, on the other hand store their energy in the roots so they may die off this year, they will come back next year. Perennial plants do not need to be covered.

Plants in containers can be moved to a spot where they will be under cover such as a porch or under an awning. Other plants such as those in large containers or planted directly in the ground need to be covered up where they are.

Materials used to cover the plants include newspaper, plastic, plastic bags, sheets or other material that can be loosely laid over the plants. If the wind is blowing its a good idea to use a covering that can be tied down but since many frosts occur on still nights this usually is not necessary.

The plants will probably need to be uncovered in the morning as the sun on plastic can cause the temperature to spike causing damage from heat. It’s a delicate balance between a quick frost and temperatures in the 80 or better but that is one of the challenges with growing in zone 4.

Every year by the end of August our temperatures start the turn back to cooler. Even the angle of the sun tells us that fall is just about here.

Another sure sign is the condition of the flowers in the garden. The sun and heat loving perennials like the daisies and black eyed Susan’s are just about spent. This year we have the added effect of the pronounced drought of the past 2 months.

This morning we assessed a garden for a customer. The main planting was creeping phlox but the blooms had long since gone and what foliage that was left was beginning to turn brown. The round garden measures about 8 feet in diameter and was situated directly beneath and around a medium small 10 inch maple tree.

The first thought that came to mind was the tree should not have mulch piled so far up on the trunk. I will never understand why people insist on building a pile of mulch against the parts of a tree which are supposed to be exposed to the air. This practice can invite disease in the bark, not to mention it makes a hiding and breeding place for destructive insect. In fact it was a near by nursery who had constructed the garden in the first place. A nursery man should know better!

But that thought aside, I came to look at the plants and recommend a plan for the fall. The phlox covered 75 percent of the area with intermittent bare spots showing weather red mulch and a bit of black landscape fabric showing through.

My first recommendation was to start watering the phlox. The garden was very dry owing to our local drought and a spotty watering regime. A garden that is sheltered under a tree, as this one was, will not get much rain when we have light showers and its deprived any dew that might form at night as well. A week or 2 of regular watering will bring the phlox back and help prepare it for the cold dry winter ahead.

My next suggestion was to use the bare spots for seasonal planting. For example since we are heading into fall and much cooler weather the homeowners could plant some mums right in 1 gallon pots. As log as they are watered they will do fine in the pots. When winter inevitably comes the mums can be bunkered with a bit more mulch and left in the ground. Then in the spring the mums can be taken up, clipped back and held over for next fall. If for texture and variety some kale can be added as well.

Other cool weather plants such as marigolds, violas and pansy’s can also be planted in the fall. These flowers are often thought of as spring planting but they are really just cool weather plants. As a matter of fact we had violas growing in December last year, and this is zone 4.

After the mums are taken up in the spring the holes can be planted with marigolds, violas, or pansy’s for the spring. The phlox will be blooming very early and should hold the color until at least June after which time warm weather plants like geraniums and portulaca can be added to the mix.

By changing the plantings for the season they can cultivate their green thumbs and enjoy a wider variety of flowers.

Now that summers on the way out we make plans for the fall.

Autumn is a perfect time of year to take care of all the work we put off due to lack of time during the busy summer. And who wants to work when it is hot and sticky.

The best way to make use of the time left before the snow flies is to make a game plan and prioritize. See what wants to be done and weigh it against what needs to get done. For example bringing in the tender plants will need to be done before frost is on the pumpkin while stacking pots and putting benches away can wait until the last minute.

We must remain mindful of the perennial stocks needs this time of year when the weather can be cool but dry. The cool weather can lull us into a false impression that the plants are fine because the temperature is not hot. In our case the plants in the beds need to be watered until the frost hits.

One chore that must not wait too long is making the greenhouse ready for plants that will be wintered over. This means making sure the plants that will be brought in are pest free and those already in the greenhouse are too. Keeping plants in a year round greenhouse can be a chore especially when we are using organic pest control.

The key is to find a good product and we use pyola. When we use it in a regular schedule it controls all the pests including fungus gnats, white flies, aphids and mealy bugs. The sad part is this product also will kill beneficial insects but we find the insects did not work in our case.

In any case we want to make sure everything is in order so we are not faced with a mad dash some night when the temperature is dipping into the teens.