Fielding Questions: Holes in tree trunk, better bloom from tulips and collecting flower seed

In this week's Fielding Questions column, Don Kinzler addresses how to prevent woodpecker damage, improving tulip blooms and collecting seeds from flowers.

Spasucker woodpeckers can injury evergreen trees like this Norway Spruce, Don Kinzler notes.
Contributed / Kerri S.
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Q: The Norway Spruce trees that border our yard are dying, and they have holes in the bark. Do you know what could be causing this? Is there anything we can do to stop it and save the ones that are still alive? – Kerri. S.

A: The holes in the trunk are made by sapsucker woodpeckers. Sap collects in the holes, which the birds then drink. Sapsucker activity can kill a tree if the holes become numerous, because the holes interrupt the tree's movement of water and nutrients within the tree.

The best way to discourage sapsucker activity, once it’s noticed, is to wrap the trunk area where they’ve begun working with burlap or aluminum foil, which usually makes the birds go elsewhere. Monitor other trees and wrap if activity starts.

As a side note, younger spruce will grow more rapidly if a circle of wood chips or shredded bark about three to five feet in diameter is maintained around the trees. This reduces competition from grass and helps increase spruce vigor and growth.

Q: What’s the secret to getting tulips to come back year after year? Mine bloom well the first year, but fizzle out after that, barely returning the following spring. – Cindy L.


A: September is the month to plant tulips and other spring-flowering bulbs like crocus, hyacinth and daffodils. Next spring’s flower buds are already pre-formed deep inside the bulb, which is why large, high-quality bulbs produce better flowers than small bargain-priced bulbs. Because the flower buds are already present and ready to pop when spring arrives, they usually bloom well the first year.

The first step in ensuring that tulips bloom strongly for many years is to begin with types that perennialize best, such as the Darwin hybrids, which includes the Apeldoorn and Impression series.

The next step is to fertilize with a well-balanced flower or bulb fertilizer about the time the tulips are blooming, and again in several weeks while the foliage is still green and healthy. Fertilizer provides the nutrition for the bulbs to recharge themselves for the next spring’s bloom. Keep all foliage intact until it’s totally dry and brown.

More gardening columns from Don Kinzler
In this week's Fielding Questions, Don Kinzler offers advice for caring for a weeping fig, tips for thinning apples, and tells readers it's not too late to wrap trees to prevent sunscald damage.

Q: Seed of some flower types, like Wave petunias, are really expensive. Will it work if I collect seed from this year’s flowers and start them next spring indoors? – Tom S.

A: Most flowers developed today are hybrids, which might or might not “come true” from seed that’s collected from the plants you’re growing this year. I’ve tried saving seed from Wave petunias and the resulting plants were inferior in growth habit, vigor and color.

On the other hand, I’ve collected seed from hybrid marigolds and the plants produced the following year were wonderfully similar to the original. Likewise, many zinnia cultivars seem to maintain their characteristics when seed is collected and planted.

Heirloom flower types are well-known for their ability to produce seed nearly identical to the original when seed is saved, including cosmos, four o’clock, cleome, nasturtium, balsam, bachelor’s buttons, celosia, nicotiana, moss rose and zinnia.

Allow seed heads to dry in flat trays after picking. Then separate seed from any chaff and store in envelopes placed inside a sealed container. Keep in the refrigerator until next spring.


If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at . Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.

Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at
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