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Plant Fall Bulbs Now for Spring Color Later

As we move further into the fall season, many gardeners have turned their attention to cleaning up and preparing to put their gardens to bed for winter. Gardeners should also take this time to plan ahead for spring blooming bulbs which are currently available in your local garden center. Now is the perfect time to add these must-have jewels to your landscape. For most areas in Colorado, you should plant these bulbs sometime between the middle of September to the end of October. I have planted bulbs as late as November during a mild fall and winter. As long as the ground is not frozen, you can plant bulbs. However, by planting in early fall you give the bulbs time to establish some roots before the soil freezes, ensuring the best success. Lucky for us, the growing conditions in much of Colorado are perfect for spring blooming bulbs. The climate and ecological conditions of many of the bulb’s native ranges are quite similar to our high plains region.

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Crocus popping up through veronica and sedums.

The diversity of size, shape and color of spring blooming bulbs is fascinating. Some of the best bulbs to plant in our area are (listed in order of bloom time) :

Early Spring Bloomers:  crocus, Siberian squill, snowdrops, dwarf iris, and species tulips

Mid-Spring Bloomers:  hyacinths, daffodils, grape muscari, fritillaria and tulips

Late  Spring Bloomers:  alliums, irises and fox-tail lillies

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Alliums with Cholla cactus.

Fall planted bulbs do best in soils that are well drained. If the soil is too wet, the bulbs may rot. The rule of thumb is to plant the bulbs at a depth 3 to 4 times the length of the bulbs. If you buy bulbs in a package, a visual guide to bulb planting depth is usually printed on the package.

Consider adding “bulb food” to the holes you’ve dug before you drop in the bulbs. Phosphorus fertilizer will give your bulbs a boost, and help them become established. Traditionally a product called “bone meal” was recommended for providing phosphorus to bulbs. But research done at Colorado State University has shown that product doesn’t work well in our typically alkaline soil chemistry. Consider a conventional (a.k.a. “non-organic”) fertilizer called “triple super phosphate”. However, using phosphorus from conventional fertilizers has been linked to environmental damage such as toxic algae blooms in lakes and rivers. Use the conventional phosphorus sparingly and carefully. If you’ve not already done so, amending your soil with compost is also a good idea to improve soil texture for your bulbs.

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Close up of foxtail lillies.

Most spring blooming bulbs do best in full sun to part sun locations as opposed to deep shade. But if the site is south facing in full sun, that area’s soil may warm up too much in late winter, causing the bulbs to flower early and those blooms would be susceptible to frost damage during cold snaps. It is a good idea to mulch the soil where you’ve planted the bulbs. Mulch will keep the soil from drying out, and help moderate soil temperature so it doesn’t warm up too quickly.

Design-wise, you can tuck just a few bulbs into niches between established perennials and ornamental grasses in your garden, or you could add large groupings of one type of bulb to get maximum color punch in your landscape. One effective way to add bulbs to an existing garden is to place them around low-growing plants that will still be dormant when the spring bulbs emerge. That approach is particularly effective with low growing groundcover perennials. Some people will add early spring bulbs such as crocus or snowdrops to a lawn area, knowing that the grass won’t start growing or need a mowing until after the bulbs are done. And if you want to add bulbs year after year, you might want to make a plan or take photos of where the existing bulbs are when they are blooming. That way you can avoid disturbing the established bulbs next time you add more in the fall.

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Tulips mingling with veronica and the remnants of last year’s ornamental grass.

For all the bulbs, you should not remove the leaves after the flowers have faded, until the leaves have turned from green to brown. Removing green leaves too early deprives the bulbs the ability to feed themselves in preparation for the next year’s blooms.

If your bulbs are “happy” where you’ve placed them, there’s a chance they will supply you with gorgeous blooms for many years. Adding spring blooming bulbs to your garden is an easy way to get dependable spots of color into your landscape for a springtime show!

This is the official blog of Outdoor Design Group, Colorado Landscape Architects.  For more information about our business and our services, click here.

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Collecting Rainwater No Longer Illegal in Colorado

Starting on August 10, 2016, it is no longer illegal for homeowners to collect the rain (or other precipitation) that has fallen on their roofs. In May 2016 Governor John Hickenlooper signed a law (House Bill 16-1005) that allows residential properties and multifamily residences with four or fewer units to use up to two rain barrels, located above ground, with a combined storage capacity of 110 gallons.

Rain barrels can only collect precipitation from rooftop downspouts, and the collected water can only be used on the same property from where it was gathered. The collected water can only be used for outdoor purposes, such as watering outdoor plants. Collected water in rain barrels can not legally be used for drinking or indoor uses.  Additionally, it should be known by rain barrel owners that operating a rain barrel does not constitute a water right. There is language in the bill that the State Engineer “may curtail rain barrel usage” if a water right holder can prove that the use of rain barrels has impacted their ability to receive their entitled water. In fact, in the bill it says the State Engineer must report to agricultural committees in the legislature in the year 2019 and 2022, on “whether the allowance of small-scale residential precipitation collection pursuant to this article has caused any discernible injury to downstream water rights.”

If you would like to learn more about rain barrels. check out Colorado State University Extension for more information.

This is the official blog of Outdoor Design Group, Colorado Landscape Architects.  For more information about our business and our services, click here.

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Photo of the Day – Firecracker Penstemon

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I took this photo of a Firecracker Penstemon (Penstemon eatonii) in my garden back in early June. We here in the Denver area were enjoying spring like weather at the time, and so the vivid red blooms of this beauty were still captivating the pedestrians in my neighborhood who passed it by. Despite its namesake, these blooms do not make it to July 4th, as this plant usually begins flowering in early to mid Spring. Behind the penstemon, you can see a blue salvia providing a lovely blue-purple counter note to the penstemon’s brilliant warm red. This particular plant is looking a little leggy. The bed where it resides gets a bit more moisture than the plant should be receiving. It is my understanding that many (if not most) of the penstemons do better on the drier side. For useful information on how best to care for penstemons, please see the list of penstemon growing tips on the High Country Gardens website. One characteristic I appreciate about Firecracker Penstemon is the foliage can be evergreen throughout our Denver winters. And, if you have hummingbirds visiting your yard, they might be happily feeding on the tubular flowers this gorgeous plant produces.

I started this plant indoors, from seed. Many of the penstemons are very easy to acquire this way. This ease of starting from seed obviously translates to the the plants reseeding themselves in the garden. However, I find they are only mild re-seeders, and not nuisance re-seeders like lamb’s ear or blanket flower.

I highly recommend you add a splash of red to your landscape with Firecracker Penstemon. If red is not the color you are after, there are several other penstemon species and hybrids to choose from that offer diverse flower colors on plants that are perfect for low-water landscapes.

This is the official blog of Outdoor Design Group, Colorado Landscape Architects.  For more information about our business and our services, click here.

 

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Dog Tuff African Dogtooth Grass: The Best Turf Grass for Hot & Dry Sites

Do you love having a lush lawn, but hate the idea of wasting water? Do you have dogs who leave unsightly dead spots in your lawn where they’ve urinated? If you answered yes to either of these questions, then Dog Tuff African Dogtooth Grass (Cynodon ‘PWIN04S’) may be the best choice of turf grass for you. Dog Tuff is drought tolerant, resistant to dog urine, thrives is full hot sun, and is soft underfoot. Dog Tuff is a sterile variety of Bermuda grass, so it won’t spread via seeds. Dog Tuff grass was developed by respected Colorado horticulturalist Kelly Grummons. Kelly is working with High Country Gardens, and Plant Select to market this product. Watch this Plant Select video to see Kelly discussing this wonderful product:

 

Kelly has been working on bringing Dog Tuff to market for over ten years. The original parentage for this grass is native to South Africa, where a lush patch of it was found on a ranch. Dog Tuff is a “warm-season” grass, so it does not green up as early as blue grass. However, as Kelly mentions in the video, Dog Tuff needs only a fraction of the water to survive as compared to bluegrass. Dog Tuff grass will grow in many soil types, but it does need full sun (6 or more hours of direct sun). Dog Tuff is rated hardy to USDA zone 5.

We recently provided design services for a public park in Arvada, Colorado, where we incorporated Dog Tuff grass into an area the park. It was planted last year and is doing well. We are excited to have this as part of a park where people can visit and see the grass in person.

If you are planning a new lawn, or if you are thinking about replacing your current lawn with a more drought tolerant type of grass, you should consider incorporating Dog Tuff African Dogtooth grass in your home landscape.

This is the official blog of Outdoor Design Group, Colorado Landscape Architects.  For more information about our business and our services, please visit our website at odgdesign.com.

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Should Aspen Trees be Planted in Denver?

Who doesn’t love seeing the golden glow of aspen leaves (Populus tremuloides) dancing in the breeze on a mountain hillside? Many gardeners living at Colorado’s lower elevations have been smitten by the quaking leaves of aspen trees and tried to bring some of that mountain magic into their own yard. But doing so reveals lessons in plant ecology, and reminds us that not every plant we want to have in our home landscapes can easily grow there.

Aspens are a “succession” tree, moving into areas where other trees and shrubs were removed by logging, fire, erosion, insects or disease. As a succession species, they are not long lived. Their presence helps lead the way to other longer living trees.

In addition, aspens are highly susceptible to insect damages and diseases. Aspens that were collected in the wild are even more prone to damage and disease, as their root system is either injured or is incomplete during collection. Nursery grown aspens are generally healthier than collected ones, but still will likely succumb to problems and a shortened life.

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A diseased aspen tree.

Most arborists and horticulturists advise against planting Aspens along the Colorado’s Front Range. The growing conditions of the Front Range are different than those areas where Aspen thrive naturally. Aspens like to grow in gravelly, moist but well-drained soil with a lower pH (more acidic) that can typically be found at higher elevations. Along Colorado’s Front Range, our soils are typically heavy clay soils that don’t drain well and have a higher pH (more alkaline). Summer weather along the Front Range is hotter and drier than in the mountains, another factor going against the health of Aspens planted east of the high country.

If you really must have the quaking leaves of aspen in your yard, only plant them if you can place them in the north or east sides of your home (due to the afternoon heat of south and west exposures) and only if it is a nursery grown tree. Keep them away from objects that might radiate too much heat to the trees such as paving. Amend the soil with organic matter in an attempt to increase the acidity of the soil, and then mulch the newly planted tree well. You might also consider adding gravel or perlite to the soil before you plant to improve drainage, and reduce the problem of heavy clay soil.

Even if you can adhere to the aforementioned criteria while planting your aspen, it’s not likely your tree will achieve the brilliant gold of the aspens at higher elevations due to differences in soil chemistry, soil texture, soil moisture, day and night temperatures, and sunlight discrepancies at the different elevations. In addition you should be on the lookout for several different diseases and insects that more readily afflict aspens planted out of their native range.

Furthermore, if you want to remove aspen trees that are established in your yard, you may get many suckers (the stems that sprout up from aspen roots) coming up in your yard for many months after you removed the main trunk.

So in my opinion, no, aspen trees should not be planted in the Denver area, because it is not likely they will do well. But if you are aware of the many shortcomings of aspens planted outside of their native range, feel free to give them a try.

This is the official blog of Outdoor Design Group, Colorado Landscape Architects.  For more information about our business and our services, click here.

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