If you’re new to flower gardening and not quite sure where to get started, these are the three varieties I would recommend. They easy-to-grow, don’t require any fancy set-ups or special tools, and they are highly productive “cut-and-come-again” flowers, so you’ll be rewarded with lots of blooms all summer long. Plus, they’re beautiful!

All three of these cut flowers can be started in cell trays indoors in the early spring to get a jumpstart on the season (they’ll bloom a few weeks earlier for you), or direct sown into the garden in early May once all threat of frost has passed. They’re all tender annuals, meaning that they cannot tolerate a frost and thrive in warm weather, and they complete their entire lifecycle within one year. More detailed information for each variety is listed below.

Cosmos

From a business perspective, if I could only grow one type of flower, it would absolutely be cosmos. Everybody loves them! They’re light, airy, delicate, and the perfect summer addition to any bouquet. Depending on when seeds are started, they typically start blooming in mid-late June, although their most productive period is towards the end of the summer as they’re a “short-day” flower that thrives in the waning daylight. I grow a couple successions (meaning I sow seeds a couple times, each a few weeks apart) just to ensure they stay fresh for our later weddings and events, though this isn’t necessary for most home gardeners.

How to Grow Cosmos

Cosmos can be started indoors in cell trays or directly out in the garden. If starting them indoors, it’s best to get them sown around 4-7 weeks prior to the last frost date. Here in Greater Philadelphia (Zone 7a), the last frost date is typically in early May, so we aim to get cosmos started in late March. To start them indoors, they’ll do well in room temperature and will require a basic grow light; a sunny window is typically not enough, unfortunately. (Our seed starting 101 article requires more in-depth information about affordable and effective seed starting.)

Place about two seeds per cell, cover them lightly, and keep them well-watered. Seeds typically germinate within a week. Once they’re about 8” tall, we recommend “pinching” them back to encourage more blooming in the summer. To do this, simply snip or pinch off the top inch or two of the plant, right above a set of leaves. This process encourages the plant to branch out and ultimately produce significantly more flowers.

Once all threat of an overnight frost has passed in early May or so, your tray of cosmos are ready to get “hardened off” and transferred to the garden. Hardening off seedlings grown indoors is a necessary step in the process to ensure the delicate seedlings build up strength to tolerate the outdoor elements. Simply bring the tray outdoors for a little bit each day, gradually increasing the length they’re outside, for at least a few days. Space them about 9” apart in the garden.

If choosing to direct sow your cosmos in the garden, they can get planted anytime from early May through early July here in Greater Philadelphia. I plant two seeds every 9” and thin them down to just one if both germinate.

Once they begin blooming, it’s important to regularly cut from them and “deadhead” them, or remove spent blooms. This will ensure that your plants continue producing flowers for a few months. And while it may seem a bit counterintuitive at first, harvesting your cosmos by cutting down further on the plant will encourage it to produce even longer stems.

Be sure to keep your cosmos in fresh water, and out of direct sunlight. They have a vase life of 4-7 days.

My favorite varieties are Afternoon White and Versailles Flush. Note that the double varieties, like “Double Click”, are quite top-heavy and tend to droop in a vase.

Celosia

Celosia is one of my favorite filler flowers for its gorgeous texture and warmth. There are a few different varieties - spicata (spike-like), plumosa (plume-like) and cristata (brain-like). I gravitate towards the plume-like blooms for my own garden, but also grow plenty of the spike-like ones for personal flowers in weddings (they look great in boutonnieres!). It’s also an excellent choice if you like to craft or enjoy working with dried flowers!

How to Grow Celosia

Celosia is grown very similarly to cosmos. While they can be started directly outdoors in May, it’s best to get them started indoors, as they take a little bit longer to go from seed to bloom. If starting them indoors, it’s best to get them sown around 5-8 weeks prior to the last frost date. Here in Greater Philadelphia (Zone 7a), the last frost date is typically in early May, so we aim to get cosmos started in mid-late March. To start them indoors, they’ll do well in room temperature and will require a basic grow light; a sunny window is typically not enough, unfortunately. (Our seed starting 101 article requires more in-depth information about affordable and effective seed starting.)

Place about two seeds per cell, cover them lightly with your seed starting mix, and keep them well-watered. Seeds typically germinate within 10 days or so. Once they’re about 8” tall, we recommend “pinching” them back to encourage more blooming in the summer. To do this, simply snip or pinch off the top inch or two of the plant, right above a set of leaves. This process encourages the plant to branch out and ultimately produce significantly more flowers.

Once all threat of an overnight frost has passed in early May or so (celosia are extremely cold sensitive), your tray is ready to get “hardened off” and transferred to the garden. Hardening off seedlings grown indoors is a necessary step in the process to ensure the delicate seedlings build up strength to tolerate the outdoor elements. Simply bring the tray outdoors for a little bit each day, gradually increasing the length they’re outside, for at least a few days. Space them about 6-12” apart in the garden, depending on package directions; each variety is a bit different.

If choosing to direct sow your celosia in the garden, they are best to get started right in early-mid May in Greater Philadelphia; starting them much later than this is likely not worthwhile, as it takes them a few months to start blooming productively. I plant two seeds every 9” and thin them down to just one if both germinate.

Celosia lasts quite long in a vase - around two weeks or so - and is excellent as a dried flower and in crafts.

My favorite varieties are the recent Floret introductions, Flamingo Feather, and Celway Terracotta.

Zinnias

It’s hard to include a list about easy-to-grow cut flowers without including zinnias! These cheery little blooms are both foolproof and productive - there aren’t many other flowers that offer the same bang for your buck that zinnias do. Zinnias thrive in the warm weather and will bloom for a couple months each summer.

How to Grow Celosia

Zinnias are grown similarly to both cosmos and celosia. These forgiving and fast-growing flowers can be started indoors in spring to give them a jumpstart on the season, about 4-6 weeks before the last frost, or they can be direct sown in the garden after the last frost. Here in Greater Philadelphia (Zone 7a), the last frost date is typically in early May, so we aim to get zinnias started in late March or early April. To start them indoors, they’ll do well in room temperature and will require a basic grow light; a sunny window is typically not enough, unfortunately. A heat mat is also a good idea for zinnias, which thrive in warmer temperatures, although it’s not absolutely necessary. (Our seed starting 101 article requires more in-depth information about affordable and effective seed starting.)

Place about two seeds per cell, cover them lightly with your seed starting mix, and keep them well-watered. Seeds typically germinate within a week. Once they’re about 8” tall, we recommend “pinching” them back to encourage more blooming in the summer. To do this, simply snip or pinch off the top inch or two of the plant, right above a set of leaves. This process encourages the plant to branch out and ultimately produce significantly more flowers.

Once all threat of an overnight frost has passed in early May or so (zinnias are very cold sensitive), your tray is ready to get “hardened off” and transferred to the garden. Hardening off seedlings grown indoors is a necessary step in the process to ensure the delicate seedlings build up strength to tolerate the outdoor elements. Simply bring the tray outdoors for a little bit each day, gradually increasing the length they’re outside, for at least a few days. Space them about 9” apart in the garden.

If choosing to direct sow your zinnias in the garden, they can get started anytime from early May-mid July in Greater Philadelphia. I plant two seeds every 9” and thin them down to just one if both germinate. Because zinnias often succumb after a couple months of blooming to a fungal disease called powdery mildew, I plant at least two or three successions (between early May-early July) to ensure that we have zinnias blooming productively for our late summer and early fall weddings.

Zinnias last quite a long time in a vase, usually at least a week or so. They are considered a “dirty” flower because their stems will cloud the vase. To prevent this, place a drop of bleach in the vase water.

My favorite varieties are the recent Floret introductions, Queeny Lime, and Zinderella Peach. I’m also looking forward to trying Johnny’s Seeds “Ballerina” this year.

The Three Easiest Cut Flowers to Grow from Seed

Direct Seeding Cool-Weather Flowers

Four Whimsical Flowers We’re Excited to Start in March