[Ozarkian]

I set up a new 20 gallon aquarium 2 days ago. I purchased a water primrose and an amazon sword.
The pet store didn't have much of a selection but I am happy to have these. My question is, how soon should I expect to see growth? Days, weeks, months? These are the first live plants I have ever had and am reading as much as I can. I have not seen anything on their growth rates though...

 

[cs_gardener]

The amazon sword will probably take a while to become established (a couple weeks is normal for me when I set up a new tank). After that you should see regular growth.

I'm not sure about the water primrose as I'm not familiar with that common name. Stem plants usually take less time to become established and start growing than rosette plants like swords. It's usually a matter of days before seeing new growth. Growth rate also depends on the conditions in your tank. More light, nutrients, and supplemental CO2 mean faster growth.

 

[Veloth]

Is This the plant you're asking about?

 

[trenac]

Water Primrose is Ludwigia repens.

Growth rate is going to depend on several factors:Type of plant, lighting, fertilizaton, C02 use. In the beginning plants use stored nutrients to grow, but once they run out the growth will stall. So that is why it is important to start a fertilization routine from day.