Ask a Master Gardener

Planting Bulbs

10/12/21

Every year I enjoy the tulips I see around town in the spring. When do I need to plant those? LW

Tulip bulbs (among others) should be planted in the fall/early winter. It’s hard to give a definite date, but you should wait until soil temperatures are in the 50s. At the time of this writing, 4” soil temperatures in our area are in the high 60s so we have a few weeks yet (probably…it is Oklahoma). But that doesn’t mean you shouldn’t go ahead and get your bulbs now because as bulbs continue to grow in popularity, they can disappear from the local garden centers and mail order houses if you wait too long. Your biggest decision will be deciding what colors and types you want to plant.

As you are shopping, one thing to consider is bloom time. Different bulbs bloom at different times. First, we have the early bloomers like crocus, hyacinth, and some tulips. Next come the mid-bloomers such as tulips and daffodils. And then there are the late spring bloomers like allium, iris, bluebells, and the rest of the tulips. Mixing these up will give you a longer flowering season rather than just a single burst of color.

Next you will need to decide where you are going to plant your bulbs (some might say we should figure this out before purchasing our bulbs, but we gardeners don’t need that kind of negativity in our lives.) For best results plant your bulbs in well-drained soil because wet soil can cause the bulbs to rot. If your location has soil with a high clay content, you should mix in some organic material such as manure or compost. These additives need to be worked into the top 12 inches of the soil. You don’t need to be overly concerned with sun requirements for spring blooming bulbs since they tend to bloom before the leaves on the trees get established. However, summer blooming bulbs will need a location with full sun.

Phosphorus is important for the success of your bulbs and to know your soil’s phosphorus levels you should do a soil test through the OSU Extension. But, if you haven’t done a soil test recently, you can mix a little bonemeal into the soil before planting. Bonemeal is about 12% phosphorus, so it is a good choice. Just follow the directions on how much to add. When you see the first signs of leaves starting to break the surface in the spring, sprinkle a little 10-10-10 fertilizer around. Do not add fertilizer after they start flowering in the spring.

Planting is a lot of fun and pretty simple. The one thing you need to be mindful of is that you should plant your bulbs two to three times as deep as the bulb is tall. This will mean different types of bulbs should be planted at different depths, depending on the bulb size. Bulbs should be planted with the larger, bulbous end down and their noses up.

There are bulb planting tools available with prices that vary from $10 to $40 dollars. I really enjoy my bulb planter, but a hand trowel also gets the job done. If you like power tools, they make an attachment for your drill to dig the hole, but that kind of destroys the garden planting vibe for me.

Now, if you have a problem with gophers in your yard, you will need to take some additional precautions since gophers seem to love to dine on bulbs. A good way to discourage gophers is to dig a trench for your bulbs, line the bottom of the trench with chicken wire, place some soil on top of the chicken wire, place your bulbs, add some more soil, cover with more chicken wire, and they bury them completely. The chicken wire will hopefully discourage gophers while also allowing the bulbs to bloom naturally.

After planting, water them in well since we want them to develop their root system before winter. A little mulch on top wouldn’t hurt either as this will help stabilize soil temperatures and protect them from a hard freeze. If you are planting early blooming bulbs like crocus or grape hyacinth, don’t cover them with mulch since this will delay the soil from warming up next year.

After the bulbs have bloomed in the spring, resist the temptation to cut down the remaining green foliage. This greenery is still at work helping the plant store energy for next year’s growth. Just leave the foliage in place until it turns yellow or dies back on its own. When the foliage dies back, the bulbs are dormant until they wake up again in the fall.

One of the questions that always comes up is “should I dig up the bulbs after dormancy or leave them in the ground?” The answer to this boils down to type of bulb and personal preference. I had some bulbs that I left in the ground against my gardener friends’ recommendations. I figured “try it and see.” Some of them flowered the next season and some didn’t. We’ll see how they do this coming spring.

Prices will vary, but I recently purchased a bag of 50 daffodil bulbs for about $17 but I’ve paid as much as $1.50 per bulb too. The more exotic the flowers, the more your bulbs will cost, so go get some bulbs and get ready to plant. Happy gardening!

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org.