Grow and Care for a Gum Plant

Grow gumweed in full sun, in soil that drains, and water it to match the kind you bought. Gum plant is Grindelia.

Give it full sun, soil that drains, and water that fits the kind you bought

Gumweed wants full sun and a hole that drains. Shade is the main reason it stays thin and blooms poorly. Water a new plant through the first season so the roots take. [1] Great Valley gumweed then wants little extra water. It takes clay, alkaline soil, and salt spray once the roots are in. [2] Puget Sound gumweed grows in salt marshes, coastal bluffs, and moist meadows. Keep that kind moist, and still give it soil that drains. [3]

1. Choose full sun. A south or west bed that drains is better than a dark north corner.
2. Set it in soil that drains. Clay, sand, or loam is fine if water does not stand around the crown.
3. Water through the first season. After that, skip extra water on Great Valley gumweed unless the plant wilts in a long drought.
4. Keep Puget Sound gumweed moist through the growing season. Do not copy a desert watering calendar onto that kind.

Plant in fall or spring, at the same depth as the pot

Knock the plant from its pot and set the root ball at the same depth it was already growing. Keep the taproot straight. Plant in fall or spring while the soil is workable, water after you plant, and water again in dry weather until the roots take.

1. Plant in fall or spring. October is a good window for Great Valley gumweed, because winter rain can settle the roots before the first dry summer.
2. Set the root ball even with the surrounding soil. Do not bury the stem deeper than it grew in the pot, and do not fold the taproot in the hole.
3. Leave about two feet between plants so the stems can branch. Great Valley gumweed can reach several feet tall. Puget Sound gumweed stays shorter.
4. Water to settle the soil. Keep the first season from baking the new roots, and do not plant into a low spot that stays wet.

Cut it back when it goes dormant

The top dies back in winter, then new stems come from the rootstock in spring. Deadhead spent heads if you want a longer bloom and fewer seedlings. When the stems go brown, cut them back.

1. Pick off spent flower heads through summer if you want more bloom and fewer volunteers.
2. When the stems go dormant, cut them back to about a foot, or to a low stub. A high cut in summer and a lower cut in fall also works.
3. Wait for new growth from the rootstock in spring before you decide a plant is dead.
4. Take out a broken stem any time. Do not shear a green plant to the ground in the heat of summer just to tidy it.

Not a eucalyptus — and not goldenrod or curlycup gumweed

Gum plant on a Grindelia tag is this sticky yellow daisy. It is not a eucalyptus. Eucalyptus is a tree with peeling bark, not a resinous daisy — see How to Grow Eucalyptus.

Goldenrod is Solidago, another late yellow daisy without the milky pad on the buds — see How to Grow Goldenrod. Sneezeweed is Helenium, a wetter border daisy — see How to Grow Sneezeweed. Curlycup gumweed is a different Grindelia that shows up on roadsides. Tarweed and tarplant are other yellow summer daisies that can hide gumweed in a dry field. If the buds glisten with white resin and the tag says Grindelia, you still have gumweed. [4]

How to grow gumweed from seed

Seed is the easy start. Sow in fall or spring, barely cover the seed, and keep the mix just moist until it sprouts. Stem cuttings rarely take, so start from seed unless you already have a plant to divide at the nursery.

1. Sow in fall or spring. Barely cover the seed, about a quarter inch, because light helps it sprout.
2. Keep the mix just moist at about 50 to 60°F. Seedlings usually show in two to three weeks. A short cool spell around 46°F can raise the germination rate a little.
3. Direct-sow in the bed, or start in small pots and transplant once the roots fill the cell. Do not twist the taproot when you move a seedling.
4. Skip cuttings unless you already know they root for you. Seed is the reliable method.

Set gumweed in full sun, in soil that drains, and water it to match the kind you bought.