QUESTION: It's that time of the year when we are seeing lots of berries on some of our native trees and shrubs. We are curious - is there an easy way to tell if they are okay to eat?

ANSWER: For beginners, let's dispel some of the most common myths regarding plant toxicity based on information from the Washington Poison Control Center.

Myth: If a bird eats the berry it is safe for humans to eat

Fact: Not true - Do not assume a plant is safe because birds or other wildlife eat it. What is poisonous to humans is not necessarily harmful to other animals.

Myth: Cooking poisonous berries makes them edible.

Fact: Not true - Do not count on heating or cooking berries or other part of a plant to destroy any toxic substances.

Myth: All berries that taste bad are poisonous.

Fact: Not true - some toxic berries taste very good, while some that are non-toxic taste very bad. You cannot tell if a berry or plant is poisonous just from the taste.

Myth: If the berries are safe to eat then the rest of the plant would be safe to eat as well.

Fact: Do not assume, just because the fruit or roots of a plant are edible, that other parts of the plant can also be eaten. Many plants with edible parts also have poisonous part. Rhubarb is perhaps the best example of this where the stalks are edible and the green leaf blades highly toxic.

The bottom line is it's impossible to remove poisonous plants from our environment. The best way to prevent poisoning is for people to learn which plants are harmful and to teach their children not to play with plants and never put them in their mouths. The Washington Poison Control Center at 1-800-222-1222 has a fact sheet which lists many of the most common garden plants including those that are both toxic and safe. A longer list which includes both common and scientific names is available at

QUESTION: It's almost September and our tomatoes are simply not ripening! What's wrong? Is there anything we can do to speed up the ripening process?

ANSWER: If your garden tomatoes look like they've been placed on hold, you're not alone! Tomato fruits go through several stages of development during their maturation process. During early stages, the fruit continues to grow in size and remains green, typically requiring 40 to 50 days. Once the fruit has reached full size (called "mature green"), changes in pigment begin to take place, causing the green to fade to light green then to the appropriate pigments for that particular cultivar, be it red, pink, yellow or orange.

Ripening and color development in tomatoes is governed primarily by two factors: temperature and the presence of naturally occurring hormone called "ethylene."

The optimum temperature range for ripening mature green tomatoes is 69 to 77 degrees F. The further temperatures stray from the optimum, the slower the ripening process will be. Furthermore, when temperatures are outside the optimum range for extended periods, conditions may become so stressful that the ripening process virtually halts.

At the same time, tomatoes do not produce lycopene and carotene, the pigments responsible for ripe tomato color, when temperatures are above 85 degrees F. Surprisingly then, extended periods of extreme heat cause tomatoes to stop ripening. The fruit often appear yellowish green to yellowish orange.

There's not much you can do but wait out the weather. As temperatures become more favorable, the ripening process should get back on track. We should have a few more weeks of good growing weather before a killing frost arrives. Even if frost does come early, keep in mind that tomatoes that have reached at least the mature green stage can be ripened of the vine.

Look for a color change to at least a lighter green - and a little bit of blush is even better. Those that are still immature green will never ripen, so save those for the compost pile. Store mature green to slightly blushed fruits at 60 to 65 degrees F, or warmer if faster ripening is desired. Ripe fruits can be stored cooler, as low as 45 degrees F. The typical home refrigerator is too chilly for storing tomatoes, Instead, pack fruits in shallow layers and keep in a well-aerated location where temperatures can be maintained.

Question: We have several huge blackberry patches in our backyard that are totally out of control. Even though we enjoy the fruit, we would like to get rid of them. What do you suggest?

Answer: Getting rid of these aggressive berry vines is never an easy task. Blackberry canes are known for their stout thorns and robust growth which can result in plants reaching 10 feet in height and spreading as much as 20 feet in a season. In addition the trailing canes can root where they contact the soil producing dense, impermeable thickets. Blackberry seeds are transported by birds and mammals that eat the fruit. The seeds can remain viable in the soil for several years.

Cutting back the canes and digging out the roots is perhaps the best option for smaller patches. Treat any new foliage which may appear with glyphosate (sold as Round-up) in September. This time of the year herbicide applications are very effective when plants are beginning to move carbohydrates from the leaves back to the roots for winter. The herbicide should be applied when the new growth is about a foot tall so there's enough live tissue to respond to the chemical. For larger thickets, you may have to use heavy equipment to help reduce the plants to the point where you can prune and apply herbicides.

EDITOR'S NOTE: For answers to local gardening questions, contact Master Gardener Earl Miller at 642-0541 or e-mail him at

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